MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX Applications

Page 1

Developing coldfusion mx applications.

Page 3: Contents

3 contents introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 using this book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 about macromedia coldfusion mx documentation . . . ....

Page 5

Contents 5 chapter 4: using expressions and pound signs . . . . . . . . . . . . . . . . . . . . . . . . 83 expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 operator types . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

Page 7

Contents 7 part ii: reusing cfml code chapter 8: reusing code in coldfusion pages . . . . . . . . . . . . . . . . . . . . . . . . 163 about reusable cfml elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 including pages with the cfinclude tag. . . . . . . . . . ....

Page 9

Contents 9 chapter 12: building custom cfxapi tags . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 what are cfx tags?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 before you begin developing cfx tags in java . . . . . . . . . . . . . . . ...

Page 11

Contents 11 accessing and changing session variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 ending a session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 configuring and using application variables . . . . . . . . . . . . . ....

Page 13

Contents 13 part iv: accessing and using data chapter 19: introduction to databases and sql . . . . . . . . . . . . . . . . . . . . . . . 411 what is a database? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 using multiple database tables . . . . ....

Page 15

Contents 15 chapter 24: building a search interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505 about verity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506 using verity with coldfusion . . . . . . . . . . . . . . . . . . ...

Page 17

Contents 17 chapter 28: charting and graphing data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617 creating a chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618 chart types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

Page 19

Contents 19 using wddx. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702 using the cfwddx tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702 validating wddx data . . . . . . . . . . . . . . . . . . . . ...

Page 21

Contents 21 part vii: using external resources chapter 35: sending and receiving e-mail . . . . . . . . . . . . . . . . . . . . . . . . . . 789 using coldfusion with mail servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790 sending e-mail messages . . . . . . . . . . . . ....

Page 23: Introduction

23 introduction developing coldfusion mx applications provides the tools needed to develop internet applications using macromedia coldfusion mx. This book is intended for web application programmers who are learning coldfusion mx or wish to extended their coldfusion mx programming knowledge. It prov...

Page 25

Using this book 25 beginning with coldfusion if you are learning coldfusion, a path such as the following might be most effective: 1 introduction to coldfusion mx through using expressions and pound signs to learn the basics of cfml. 2 introduction to databases and sql through updating your database...

Page 27: Chapter 1

27 chapter 1 introduction to coldfusion mx this chapter describes macromedia coldfusion mx and the role it plays in internet applications, including macromedia flash mx based applications. This chapter also introduces the topics discussed in this book. Contents about internet applications and web ap...

Page 29

About internet applications and web application servers 29 to extend the capabilities of a web server, you use a web application server, a software program that extends the web server’s capabilities to do tasks such as those in the preceding list. How a web server and web application server work tog...

Page 31

About coldfusion mx 31 cfml includes approximately one hundred tags. Coldfusion tags serve many functions. They provide programming constructs, such as conditional processing and loop structures. They also provide services, such as charting and graphing, full-text search, access to protocols such as...

Page 33

About j2ee and the coldfusion architecture 33 • flash mx development application debugger lets you trace your application logic as it executes between flash and coldfusion. • coldfusion mx server-side actionscript lets flash programmers familiar with actionscript create coldfusion services, such as ...

Page 35

Coldfusion features described in this book 35 application security coldfusion provides mechanisms, including the cflogin tag, for authenticating users and authorizing them to access specific sections of your application. You can also use resource security, which secures access to coldfusion resource...

Page 37

The cfml programming language this part describes the elements of the cfml programming language. It tells you how to use cfml tags, functions, variables and expressions, the cfscript scripting language, and regular expressions. The following chapters are included: chapter 2: elements of cfml . . . ....

Page 40

40 chapter 2: elements of cfml introduction this chapter introduces and describes the basic elements of cfml. These elements make cfml a powerful tool for developing interactive web applications. Because cfml is a dynamic application development tool, it has many of the features of a programming lan...

Page 42

42 chapter 2: elements of cfml cfml custom tags when you write a custom tag in cfml, you can take advantage of all the features of the coldfusion language, including all built-in tags and even other custom tags. Cfml custom tags can include body sections and end tags. Because they are written in cfm...

Page 44

44 chapter 2: elements of cfml constants the value of a constant does not change during program execution. Constants are simple scalar values that you can use within expressions and functions, such as “robert trent jones” and 123.45. Constants can be integers, real numbers, time and date values, boo...

Page 46

46 chapter 2: elements of cfml for more information on coldfusion data types, see chapter 3, “using coldfusion variables,” on page 53 . Coldfusion components coldfusion components encapsulate multiple, related, functions. A coldfusion component is essentially a set of related user-defined functions ...

Page 48

48 chapter 2: elements of cfml cfswitch, cfcase, and cfdefaultcase the cfswitch , cfcase , and cfdefaultcase tags let you select among different code blocks based on the value of an expression. Coldfusion processes these tags as follows: 1 the cfswitch tag evaluates an expression. The cfswitch tag b...

Page 50

50 chapter 2: elements of cfml cfabort and cfexit the cfabort tag stops processing of the current page at the location of the cfabort tag. Coldfusion returns to the user or calling tag everything that was processed before the cfabort tag. You can optionally specify an error message to display. You c...

Page 52

52 chapter 2: elements of cfml.

Page 54

54 chapter 3: using coldfusion variables creating variables you create most coldfusion variables by assigning them values. (you must use the arraynew function to create arrays.) most commonly, you create variables by using the cfset tag. You can also use the cfparam tag, and assignment statements in...

Page 56

56 chapter 3: using coldfusion variables data type notes although coldfusion variables do not have types, it is often convenient to use “variable type” as a shorthand for the type of data that the variable represents. Coldfusion can validate the type of data contained in form fields and query parame...

Page 58

58 chapter 3: using coldfusion variables to insert a pound sign in a string, you must escape the pound sign, as follows: "this is a pound sign ##" lists coldfusion includes functions that operate on lists, but it does not have a list data type. In coldfusion, a list is just a string that consists of...

Page 60

60 chapter 3: using coldfusion variables how coldfusion stores dates and times coldfusion stores and manipulates dates and times as date-time objects. Date-time objects store data on a time line as real numbers. This storage method increases processing efficiency and directly mimics the method used ...

Page 62

62 chapter 3: using coldfusion variables you can use either of the following methods to reference elements stored in a structure: • structurename.Keyname • structurename["keyname"] the following examples show these methods: depts.John="sales" depts["john"]="sales" when you assign an existing structu...

Page 64

64 chapter 3: using coldfusion variables using a query column when you are not inside a cfloop , cfoutput , or cfmail tag that has a query attribute, you can treat a query column as an array. However, query column references do not always behave as you might expect. This section explains the behavio...

Page 66

66 chapter 3: using coldfusion variables for example, assume you have the following code: if a variable myvar does not exist, it does the following: 1 creates a structure named myvar. 2 creates a structure named a in the structure myvar. 3 creates a key named b in myvar.A. 4 gives it the value "this...

Page 68

68 chapter 3: using coldfusion variables the following table explains how conversions are performed. The first column shows values to convert. The remaining columns show the result of conversion to the listed data type. Coldfusion cannot convert complex types, such as arrays, queries, and com object...

Page 70

70 chapter 3: using coldfusion variables however, if myvariable has a numeric value such as 12, only the first example produces a result. In the second case, the value of myvariable is not converted to a boolean data type, because the is operator does not require a specific data type and just tests ...

Page 72

72 chapter 3: using coldfusion variables example 2 true and 2 * 3 result value as string: "yes" explanation: 6 is converted to boolean true because it is nonzero; true and true is true. Example 3 "five is " & 5 result value as string: "five is 5" explanation: 5 is converted to the string "5". Exampl...

Page 74

74 chapter 3: using coldfusion variables caution: to prevent data corruption, you lock code that uses session, application, or server scope variables. For more information, see chapter 15, “using persistent data and locking,” on page 315 . Session contains variables that are associated with one clie...

Page 76

76 chapter 3: using coldfusion variables cffile yes following an invocation of cffile . A cffile tag. Cookie no for one client in one or more applications and pages, over multiple browser sessions. A cfcookie tag. You can also set memory-only cookies by specifying the prefix cookie when you create t...

Page 78

78 chapter 3: using coldfusion variables caution: do not call structclear (session) to clear session variables. This deletes the sessionid , cfid , and cftoken built-in variables, effectively ending the session. If you want to use structclear to delete your application variables, put those variables...

Page 80

80 chapter 3: using coldfusion variables • with only the name attribute to test that a required variable exists. If it does not exist, the coldfusion server stops processing the page and displays an error message. • with the name and default attributes to test for the existence of an optional variab...

Page 82

82 chapter 3: using coldfusion variables passing variables to custom tags and udfs the following sections describe rules for how data gets passed to custom tags and user-defined functions that are written in cfml, and to cfx custom tags that are written in java or c++. Passing variables to cfml tags...

Page 84

84 chapter 4: using expressions and pound signs expressions coldfusion expressions consist of operands andoperators. Operands are comprised of constants and variables. Operators, such as the multiplication symbol, are the verbs that act on the operands; functions are a form of operator. The simplest...

Page 86

86 chapter 4: using expressions and pound signs alternative notation for decision operators you can replace some decision operators with alternative notations to make your cfml more compact, as shown in the following table: decision operator rules the following rules apply to decision operators: • w...

Page 88

88 chapter 4: using expressions and pound signs function syntax the following table shows function syntax and usage guidelines: all functions return values. In the following example, the cfset tag sets a variable to the value returned by the now function: you can use the values returned by functions...

Page 90

90 chapter 4: using expressions and pound signs note: you do not need to use pound signs when you use the cfset tag to assign one variable’s value to another value. For example, the following tag assigns the value of the oldvar variable to the new variable, newvar: . Using pound signs in tag bodies ...

Page 92

92 chapter 4: using expressions and pound signs dynamic expressions and dynamic variables this section discusses the advanced topics of dynamic expressions, dynamic evaluation, and dynamic variable naming. Many coldfusion programmers never encounter or need to use dynamic expressions. However, dynam...

Page 94

94 chapter 4: using expressions and pound signs dynamic variable limitation when you use a dynamic variable name in quotes on the left side of an assignment, the name must be either a simple variable name or a complex name that uses object.Property notation (such as mystruct.#keyname#). You cannot u...

Page 96

96 chapter 4: using expressions and pound signs reviewing the code the following table describes how coldfusion processes this code: as you can see, using dynamic expressions can result in substantial expression evaluation overhead, and the code can be confusing. Therefore, you should avoid using dy...

Page 98

98 chapter 4: using expressions and pound signs in the second line, enclosing the myvar#i# variable name in quotation marks tells coldfusion to evaluate the name and process any text in pound signs as a variable or function. Coldfusion replaces the #i# with the value of the variable i, so that if th...

Page 100

100 chapter 4: using expressions and pound signs checked> passthrough = "readonly = 'true'"> passthrough = "readonly = 'true'"> 2 save the page as shoppingcartform.Cfm. Reviewing the code the following table describes the code: code description cartitems=4; cart = arraynew(1); for ( i=1; i le #carti...

Page 102

102 chapter 4: using expressions and pound signs reviewing the code the following table describes the code: code description run the cfml on this page only if it is called by submitting a form. This is not needed if there are separate form and action pages, but is required if the form and action pag...

Page 104

104 chapter 5: using arrays and structures about arrays traditionally, an array is a tabular structure used to hold data, much like a spreadsheet table with clearly defined limits and dimensions. In coldfusion, you typically use arrays to temporarily store data. For example, if your site lets users ...

Page 106

106 chapter 5: using arrays and structures basic array techniques the following sections describe how to reference array elements, create arrays, add and remove array elements, and copy arrays. Referencing array elements you reference array elements by enclosing the index with brackets: arrayname[x]...

Page 108

108 chapter 5: using arrays and structures adding elements to an array you can add an element to an array by assigning the element a value or by using a coldfusion function. Adding an array element by assignment you can add elements to an array by defining the value of an array element, as shown in ...

Page 110

110 chapter 5: using arrays and structures change the values in the new array. Contents of the original array after the changes: contents of the new array after the changes: the change to the new array also changes the contents of the structure in the original array. To make a complete copy of an ar...

Page 112

112 chapter 5: using arrays and structures populating an array from a query when populating an array from a query, keep the following things in mind: • you cannot add query data to an array all at once. A looping structure is generally required to populate an array from a query. • you can reference ...

Page 114

114 chapter 5: using arrays and structures a structure’s key must be a string. The values associated with the key can be any valid coldfusion value or object. It can be a string or integer, or a complex object such as an array or another structure. Because structures can contain any kind of data the...

Page 116

116 chapter 5: using arrays and structures creating and using structures this section explains how to create and use structures in coldfusion. The sample code in this section uses a structure called employee, which is used to add new employees to a corporate information system. Creating structures y...

Page 118

118 chapter 5: using arrays and structures to discover whether a specific structure contains data, use the structisempty function, as follows: structisempty(structure_name) this function returns true if the structure is empty, and false if it contains data. Finding a specific key and its value to de...

Page 120

120 chapter 5: using arrays and structures change a string, array element, and structure value in the structcopy copy. Original structure copied structure duplicated structure structure reference change a string, array element, and structure value in the duplicate original structure copied structure...

Page 122

122 chapter 5: using arrays and structures structure example structures are particularly useful for grouping together a set of variables under a single name. The example in this section uses structures to collect information from a form, and to submit that information to a custom tag, named cf_addem...

Page 124

124 chapter 5: using arrays and structures example file addemployee.Cfm the following file is an example of a custom tag used to add employees. Employee information is passed through the employee structure (the empinfo attribute). For databases that do not support automatic key generation, you must ...

Page 126

126 chapter 5: using arrays and structures all functions except structdelete throw an exception if a referenced key or structure does not exist. For more information on these functions, see cfml reference. Structfindvalue searches through a structure for the specified simple data value (for example,...

Page 128

128 chapter 6: extending coldfusion pages with cfml scripting about cfscript cfscript is a language within a language. It is a scripting language that is similar to javascript but is simpler to use. Also, unlike javascript, cfscript only runs on the coldfusion server; it does not run on the client s...

Page 130

130 chapter 6: extending coldfusion pages with cfml scripting the following rules apply to statements: • you must put a semicolon at the end of a statement. • line breaks are ignored. A single statement can cross multiple lines. • white space is ignored. For example, it does not matter whether you p...

Page 132

132 chapter 6: extending coldfusion pages with cfml scripting using cfscript statements the following sections describe how to use these cfscript statements: • assignment statements and functions • conditional processing statements • looping statements using assignment statements and functions cfscr...

Page 134

134 chapter 6: extending coldfusion pages with cfml scripting • the statements following the colon in a case statement block do not have to be in braces. If a constant value equals the switch expression, coldfusion executes all statements through the break statement. • the break statement at the end...

Page 136

136 chapter 6: extending coldfusion pages with cfml scripting if(find("key",strings[indx],1)) { writeoutput("found key at " & indx & "."); break; } else if (indx is arraylen(strings)) { writeoutput("exited at " & indx & "."); break; } } this example shows one important issue that you must remember w...

Page 138

138 chapter 6: extending coldfusion pages with cfml scripting note: unlike the cfloop tag, cfscript for-in loops do not provide built-in support for looping over queries and lists. Using continue and break statements the continue and break statements enable you to control the processing inside loops...

Page 140

140 chapter 6: extending coldfusion pages with cfml scripting cfscript example the example in this section uses the following cfscript features: • variable assignment • function calls • for loops • if-else statements • writeoutput functions • switch statements the example uses cfscript without any o...

Page 142

142 chapter 6: extending coldfusion pages with cfml scripting if (structkeyexists(rejectcode,applicant)) { switch(rejectcode[applicant]) { case "score": writeoutput("reject reason: score was too low."); break; case "late": writeoutput("reject reason: application was late."); break; default: writeout...

Page 144

144 chapter 7: using regular expressions in functions about regular expressions in traditional string matching, as used by the coldfusion find and replace functions, you provide the string pattern to search for and the string to search. The following example searches a string for the pattern " big "...

Page 146

146 chapter 7: using regular expressions in functions note: the * only applies to the character set that immediately precedes it, not to the entire regular expression. A + after the closing square bracket specifies to find one or more occurrences of the character set. You interpret the regular expre...

Page 148

148 chapter 7: using regular expressions in functions the following table describes the special characters for regular expressions: special character description \ a backslash followed by any special character matches the literal character itself, that is, the backslash escapes the special character...

Page 150

150 chapter 7: using regular expressions in functions you must be aware of the following considerations when using special characters in character sets, such as [a-z]: • to include a hyphen (-) in the square brackets of a character set as a literal character, you cannot escape it as you can other sp...

Page 152

152 chapter 7: using regular expressions in functions using backreferences you use parenthesis to group components of a regular expression into subexpressions. For example, the regular expression "(ha)+" matches one or more occurrences of the string "ha". Coldfusion performs an additional operation ...

Page 154

154 chapter 7: using regular expressions in functions for example, the following statement replaces the uppercase string "hello" with a lowercase "hello". This example uses backreferences to perform the replacement. For more information on using backreferences, see “using backreferences in replaceme...

Page 156

156 chapter 7: using regular expressions in functions the following figure shows the output of the cfdump tag: if you include subexpressions in your regular expression, each element of pos and len after element one contains the position and length of the first occurrence of each subexpression in the...

Page 158

158 chapter 7: using regular expressions in functions however, sometimes you might want to override this default behavior to find the shortest string that matches the regular expression. Coldfusion includes minimal-matching quantifiers that let you specify to match on the smallest string. The follow...

Page 160

160 chapter 7: using regular expressions in functions the following perl statements are not supported: • lookbehind (? • \x{hhhh} • • \p • \c an excellent reference on regular expressions is mastering regular expressions, by jeffrey e. F. Friedl, o'reilly & associates, inc., 1997, isbn: 1-56592-2...

Page 163: Chapter 8

163 chapter 8 reusing code in coldfusion pages this chapter describes techniques for reusing code in coldfusion pages. These techniques let you write your code once and use it, without copying it, in many places. This chapter describes the techniques and their features, and provides advice on select...

Page 165

Including pages with the cfinclude tag 165 the model of an included page is that it is part of your page; it just resides in a separate file. The cfinclude tag cannot pass parameters to the included page, but the included page has access to all the variables on the page that includes it. The followi...

Page 167

Using custom cfml tags 167 consider using udfs in the following circumstances: • you must pass in a number of arguments, process the results, and return a value. Udfs can return complex values, including structures that contain multiple simple values. • you want to provide logical units, such as dat...

Page 169

Using cfx tags 169 recommended uses coldfusion custom tags let you abstract complex code and programming logic into simple units. These tags let you maintain a cfml-like design scheme for your code. You can easily distribute your custom tags and share tags with others. For example, the macromedia co...

Page 171

Selecting among coldfusion code reuse methods 171 recommended uses consider using coldfusion components when doing the following: • creating web services. (to create web services in coldfusion, you must use components.) • creating services that are callable by flash clients. • creating libraries of ...

Page 173: Chapter 9

173 chapter 9 creating and using custom cfml tags this chapter describes how to create and use custom cfml tags that encapsulate common code. Contents creating custom tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 passing data t...

Page 175

Creating custom tags 175 5 view callingdate.Cfm in your browser. This custom tag returns the current date in the format dd-mmm-yy. As you can see from this example, creating a custom tag in cfml is no different from writing any coldfusion page. You can use all cfml constructs, as well as html. You a...

Page 177

Passing data to custom tags 177 securing custom tags the coldfusion security framework enables you to selectively restrict access to individual tag files and tag directories. This can be an important safeguard in team development. For details, see configuring and administering coldfusion mx. Accessi...

Page 179

Passing data to custom tags 179 • use the cfparam tag with a default attribute at the top of a custom tag to test for and assign defaults for optional attributes that are passed from a calling page. For example: • use the cfparam tag or a cfif tag with an isdefined function at the top of a custom ta...

Page 181

Managing custom tags 181 custom tag processing reserves the attributecollection attribute to refer to the structure holding a collection of custom tag attributes. If attributecollection does not refer to such a collection, coldfusion generates a template exception. The following example uses an attr...

Page 183

Executing custom tags 183 the following example accesses the executionmode variable of the thistag structure from within a custom tag: handling end tags the examples of custom tags shown so far in this chapter all reference a custom tag using just a start tag, as in: in this case, coldfusion calls t...

Page 185

Executing custom tags 185 processing body text body text is any text that you include between the start and end tags when you call a custom tag; for example: happy birthday ellen! May you have many more! In this example, the two lines of code after the start tag are the body text. You can access the...

Page 187

Nesting custom tags 187 nested custom tags operate through three modes of processing, which are exposed to the base tags through the variable thistag.Executionmode : • the start mode, in which the base tag is processed for the first time. • the inactive mode, in which sub tags and other code contain...

Page 189

Nesting custom tags 189 the code accessing sub-tag attributes in the base tag could look like the following: ancestor data access the ancestor’s data is represented by a structure object that contains all the ancestor’s data. The following functions provide access to ancestral data: • getbasetaglist...

Page 191: Chapter 10

191 chapter 10 writing and calling user-defined functions this chapter describes how to create and call user-defined functions (udfs). Contents about user-defined functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 calling user-defined func...

Page 193

Creating user-defined functions 193 you might call the function with argument names, as follows: interest: #totalinterest(principal=form.Principal, annualpercent=form.Percent, months=form.Months)# creating user-defined functions you can use tags or cfscript to create a udf. Each technique has advant...

Page 195

Creating user-defined functions 195 the following sections describe the general rules for using the arguments scope as an array and a structure. For more information on using the arguments scope in functions defined using cfscript, see “using the arguments scope in cfscript” on page 199 . For more i...

Page 197

Creating user-defined functions 197 using the arguments scope as a structure the following rule applies when referencing arguments scope as a structure: • use the argument names as structure keys. For example, if your function definition includes a principal argument, refer to the argument as argume...

Page 199

Creating user-defined functions 199 a simple cfscript example the following example function adds the two arguments and returns the result: function sum(a,b) { var sum = a + b; return sum; } in this example, a single line declares the function variable and uses an expression to set it to the value t...

Page 201

Creating user-defined functions 201 you must use cfargument tags for required function arguments. All cfargument tags must precede any other cfml code in cffunction tag body. Therefore, put the cfargument tags immediately following the cffunction opening tag. The cfargument tag takes the following a...

Page 203

Calling functions and using variables 203 referencing caller variables a function can use and change any variable that is available in the calling page, including variables in the caller’s variables (local) scope, as if the function was part of the calling page. For example, if you know that the cal...

Page 205

A user-defined function example 205 reviewing the code the following table describes the code: defining the function using the cffunction tag the following code replaces cfscript statements with their equivalent cfml tags. (((1+ interestrate)^years)-1)> code description function totalinterest(princi...

Page 207

Using udfs effectively 207 selecting a function scope the following table describes the advantages and disadvantages of scopes that you might considering using for your functions: using the request scope you can effectively manage functions that are used in application pages and custom tags by doing...

Page 209

Using udfs effectively 209 for example, the following code defines a function to combine a single first name and last name to make a full name. It queries the companyinfo database to get the first and last names of all employees, then it uses a cfoutput tag to loop through the query and call the fun...

Page 211

Using udfs effectively 211 passing arrays if you want your function to modify the caller’s copy of the array, the simplest solution is to pass the array to the function and return the changed array to the caller in the function return statement. In the caller, use same variable name in the function ...

Page 213

Using udfs effectively 213 for example, the following variation on a “hello world” function displays an error message if you do not enter a name in the form: enter your name: function hellofriend(name) { if (name is "") writeoutput("you forgot your name!"); else writeoutput("hello " & name &"!"); re...

Page 215

Using udfs effectively 215 reviewing the code the following table describes the code that has been changed or added to the previous version of this example. For a description of the initial code, see “a user-defined function example” on page 204 . Calling the function the code that calls the functio...

Page 217

Using udfs effectively 217 generating exceptions in udfs if you define your function using the cffunction tag, you can use the cfthrow and cfrethrow tags to throw errors to the page that called the function. You can use this technique whenever your udf identifies an error, instead of displaying a me...

Page 219: Chapter 11

219 chapter 11 building and using coldfusion components coldfusion components (cfcs) let you do the following tasks: • encapsulate and reuse code in logical units. • build applications that take advantage of cfc object-oriented features. • generate web services. • create services for macromedia flas...

Page 221

About coldfusion components 221 this chapter describes how to use cfc object-oriented features. It does not discuss general object-oriented programming concepts or methods. When to use cfcs you can use cfcs in several ways: • to develop structured, reusable coldfusion code • to create web services •...

Page 223

About coldfusion components 223 elements of a cfc a cfc definition has the following characteristics: • it is a single cfml page with a .Cfc file extension. The component name is the same as the filename. For example, if the file is mycomponent.Cfc, the component name is mycomponent. • the page is s...

Page 225

Using coldfusion components 225 • if you invoke a cfc method remotely, using a specific url, form field, flash remoting mx, or a web service invocation, coldfusion looks in the specified path relative to the web root. For form fields and urls specified directly on local web pages, coldfusion also se...

Page 227

Using coldfusion components 227 to invoke a method of a component instance using the cfinvoke tag: 1 create a file named telltime2.Cfc with the following code: servertime=now(); utctime=gettimezoneinfo(); utcstruct=structnew(); utcstruct.Hour=datepart("h", servertime); utcstruct.Minute=datepart("n",...

Page 229

Using coldfusion components 229 passing parameters using the cfinvokeargument tag to pass parameters in the cfinvoke tag body, use the cfinvokeargument tag. Using the cfinvokeargument tag, for example, you can build conditional processing that passes a different parameter based on user input. The fo...

Page 231

Using coldfusion components 231 note: to use url invocation, you must set the cffunction tag’s access attribute to remote. To pass parameters to component methods using a url, append the parameters to the url in standard url query-string, name-value pair syntax; for example: http://localhost:8500/co...

Page 233

Using coldfusion components 233 introspection: getting information about components coldfusion provides several ways to get information about components: • requesting a component page from the browser • using the coldfusion component browser • using the dreamweaver component browser • using the getm...

Page 235

Building coldfusion components 235 using the getmetadata function the cfml getmetadata function returns a structure containing all the metadata of a cfc instance. This structure contains substantially more data about the cfc than cfdump shows, and includes the following information: • all attributes...

Page 237

Building coldfusion components 237 the following cffunction tag attributes are used only for cfcs: • the displayname and hint attributes document the cfc; for more information, see “documenting cfcs” on page 240 . • the access attribute controls access to the cfc; for more information , see “using a...

Page 239

Building coldfusion components 239 in the example, the cfargument attributes specify the following: • the name attributes define the parameter names • the type attribute for the lastname argument specifies that the parameter must be a text string. The type attribute for the cost argument specifies t...

Page 241

Building coldfusion components 241 in this case, a coldfusion page with the following code sets the metatypeinfo variable to float: note: avoid using expressions in custom metadata attributes. Using expressions in metadata attributes can cause unpredictable behavior, because all metadata expressions...

Page 243

Building coldfusion components 243 example: sharing the variables scope the following example shows how a cfc can change data in the calling page’s variables scope. The callgreetme.Cfm page before invoking the cfc variables.Myname is #variables.Myname#. Calling greetme cfc. It returns: #mygreetings....

Page 245

Building coldfusion components 245 • the super keyword lets a component that overrides a base component method execute the original base component method. This technique lets your subclassed component override a method without losing the ability to call the original version of the method. The follow...

Page 247

Building coldfusion components 247 using component packages components stored in the same directory are members of a component package. Component packages help prevent naming conflicts and facilitate easy component deployment. For example: • coldfusion searches the current directory first for a cfc....

Page 249

Building coldfusion components 249 using role-based security if you specify a roles attribute in a cffunction tag, as the following example shows, only users who are logged in with one of the specified roles can execute the function: when a user tries to invoke a method that he or she is not authori...

Page 251: Chapter 12

251 chapter 12 building custom cfxapi tags sometimes, the best approach to application development is to develop elements of your application by building executables to run with coldfusion. Perhaps the application requirements go beyond what is currently feasible in cfml. Perhaps you can improve app...

Page 253

Writing a java cfx tag 253 setting up your development environment to develop cfx tags in java you can use a wide range of java development environments, including the java development kit (jdk) version 1.3.1 from sun, to build java cfx tags. You can download the jdk from sun http://java.Sun.Com/j2s...

Page 255

Writing a java cfx tag 255 2 save the file in a directory configured to serve coldfusion pages. For example, you can save the file as c:\inetpub\wwwroot\cfdocs\testjavacfx.Cfm on windows or /home/docroot/cfdocs/ testjavacfx.Cfm on unix. 3 if you have not already done so, register the cfx tag in the ...

Page 257

Zipbrowser example 257 automatic class reloading you can determine how the server treats changed java cfx class files by specifying the reload attribute when you use a cfx tag in your coldfusion page. The following table describes the allowable values for the reload attribute: the default value is r...

Page 259

Approaches to debugging java cfx tags 259 approaches to debugging java cfx tags java cfx tags are not stand-alone applications that run in their own process, like typical java applications. Rather, they are created and invoked from an existing process. This makes debugging java cfx tags more difficu...

Page 261

Developing cfx tags in c++ 261 { "lynne", "teague", "developer" } } ; debugquery query = new debugquery( "employees", columns, data ) ; // create tag, process debugging request, and print results outputquery tag = new outputquery() ; debugrequest request = new debugrequest( attributes, query ) ; deb...

Page 263

Developing cfx tags in c++ 263 registering cfx tags to use a cfx tag in your coldfusion applications, first register it in the extensions, cfx tags page in the coldfusion mx administrator. To register a c++ cfx tag: 1 on the coldfusion mx administrator server tab, select extensions > cfx tags to ope...

Page 265: Part III

Part iii developing cfml applications this part describes how to develop coldfusion applications. It describes the elements of a coldfusion application and how to structure an application, handle errors, use variables that are shared among pages, lock code segments, and secure your application. It a...

Page 268

268 chapter 13: designing and optimizing a coldfusion application about applications the term application can mean many things. An application can be as simple as a guest book or as sophisticated as a full internet commerce system with catalog pages, shopping carts, and reporting. However, an applic...

Page 270

270 chapter 13: designing and optimizing a coldfusion application for an overview of these elements, and information about how to choose among them, see chapter 8, “reusing code in coldfusion pages,” on page 163 . Shared variables the following coldfusion variable scopes maintain data that lasts bey...

Page 272

272 chapter 13: designing and optimizing a coldfusion application you can divide your logical web application into multiple coldfusion applications by using multiple application.Cfm pages with different application names. Alternatively, you can use multiple application.Cfm pages that specify the sam...

Page 274

274 chapter 13: designing and optimizing a coldfusion application defining page processing settings the cfsetting tag lets you specify the following page processing attributes that you might want to apply to all pages in your application: often, you use the cfsetting tag on individual pages, but you...

Page 276

276 chapter 13: designing and optimizing a coldfusion application reviewing the code the following table describes the code and its function: code description clientmanagement="yes" clientstorage="mycompany" sessionmanagement="yes"> names the application, enables client and session scope variables, ...

Page 278

278 chapter 13: designing and optimizing a coldfusion application • the directory on the server in which to store the cached pages. The default directory is cf_root/ cache. It is a good practice to create a separate cache directory for each application. Doing so can prevent the cfcache tag flush act...

Page 280

280 chapter 13: designing and optimizing a coldfusion application #application.Productcache# reviewing the code the following table describes the code and its function: code description welcome to our home page. The time is #timeformat(now())#. Your lucky number is: #randrange(1,1000)# displays the ...

Page 282

282 chapter 13: designing and optimizing a coldfusion application variable = foo dbvarname = @param2> the output param value: '#foo#' the results information variable = foo dbvarname = @param2> the output param value: '#foo#' #name#,#date_col# record count: #rs1.Recordcount# columns: #rs1.Columnlist...

Page 284

284 chapter 13: designing and optimizing a coldfusion application you must use the createtimespan function to specify the cachedwithin attribute value (in days, hours, minutes, seconds format). For example, the following code caches the results of getting the contents of the employees table of the c...

Page 286

286 chapter 14: handling errors about error handling in coldfusion by default, coldfusion generates its own error messages when it encounters errors. In addition, it provides a variety of tools and techniques for you to customize error information and handle errors when they occur. You can use any o...

Page 288

288 chapter 14: handling errors about coldfusion exceptions you can categorize coldfusion exceptions in two ways: • when they occur • their type when exceptions occur coldfusion errors can occur at two times, when the cfml is compiled into java and when the resulting java executes, called runtime ex...

Page 290

290 chapter 14: handling errors advanced exception types the advanced exceptions consist of a set of specific, narrow exception types. These types are supported in coldfusion mx for backward-compatibility. For a list of advanced exception types, see “advanced exception types” in chapter 2, “coldfusi...

Page 292

292 chapter 14: handling errors tip: if you get a message that does not explicitly identify the cause of the error, check the key system parameters, such as available memory and disk space. Determining error-handling strategies coldfusion provides you with many options for handling errors, particula...

Page 294

294 chapter 14: handling errors specifying custom error messages with cferror custom error pages let you control the error information that users see. You can specify custom error pages for different types of errors and handle different types of errors in different ways. For example, you can create ...

Page 296

296 chapter 14: handling errors the following table describes the variables available on error pages: exception error pages can also use all of the exception variables listed in the section “exception information in cfcatch blocks” on page 301 . To use these variables, replace the cfcatch prefix wit...

Page 298

298 chapter 14: handling errors the cflog tag lets you specify the following information: • a custom file or standard coldfusion log file in which to write the message. • text to write to the log file. This can include the values of all available error and cfcatch variables. • message severity (type...

Page 300

300 chapter 14: handling errors for example, you can use cftry to catch errors in code that enters data from a user registration form to a database. The cfcatch code could do the following: 1 retry the query, so the operation succeeds if the resource was only temporarily unavailable. 2 if the retrie...

Page 302

302 chapter 14: handling errors note: if you use cfdump to display the cfcatch variable, the display does not include variables that do not have values. The cfcatch.Tagcontext variable contains an array of tag information structures. Each structure represents one level of the active tag context at t...

Page 304

304 chapter 14: handling errors department: #dept_id# last name: #lastname# first name: #firstname#.

Page 306

306 chapter 14: handling errors reviewing the code the following table describes the code: code description initializes the employee id to a valid value. An application would get the value from a form or other source. Sets the default errorcaught variable value to the empty string (to indicate no er...

Page 308

308 chapter 14: handling errors catching and displaying thrown errors the cfcatch tag catches a custom exception when you use any of the following values for the cfcatch type attribute: • the custom exception type specified in the cfthrow tag. • a custom exception type that hierarchically matches th...

Page 310

310 chapter 14: handling errors • the custom tag finds all records in the companyinfo database with a matching last name, and returns the results in a caller variable. If it fails to connect with the main database, it tries a backup database. The calling page the calling page represents a section fr...

Page 312

312 chapter 14: handling errors reviewing the code the following table describes the code: code description message = "last name was not supplied to the cf_getemps tag."> makes sure the calling page specified an empname attribute. If not, throws a custom error that indicates the problem and exits th...

Page 314

314 chapter 14: handling errors.

Page 316

316 chapter 15: using persistent data and locking about persistent scope variables coldfusion mx provides four variable scopes, described in the following table, that let you maintain data that must be available to multiple applications or users or must last beyond the scope of the current request. ...

Page 318

318 chapter 15: using persistent data and locking managing the client state because the web is a stateless system, each connection that a browser makes to a web server is unique to the web server. However, many applications must keep track of users as they move through the pages within the applicati...

Page 320

320 chapter 15: using persistent data and locking to use coldfusion client or session variables without using cookies, each page must pass the cfid and cftoken values to any page that it calls as part of the request url. If a page contains any html href a= links, cflocation tags, form tags, or cffor...

Page 322

322 chapter 15: using persistent data and locking the coldfusion mx administrator client variables page controls the default client variable location. You can override the default location by specifying a clientstorage attribute in the cfapplication tag. You can specify the following values in the c...

Page 324

324 chapter 15: using persistent data and locking creating a client variable to create a client variable and set its value, use the cfset or cfparam tag and use the client scope identifier as a variable prefix; for example: after you set a client variable this way, it is available for use within any...

Page 326

326 chapter 15: using persistent data and locking exporting the client variable database if your client variable database is stored in the windows system registry and you need to move it to another machine, you can export the registry key that stores your client variables and take it to your new ser...

Page 328

328 chapter 15: using persistent data and locking enabling session variables in your application you must also enable session variables in the cfapplication tag in your application.Cfm file. Do the following in the application.Cfm file to enable session variables: • set sessionmanagement="yes" • use...

Page 330

330 chapter 15: using persistent data and locking accessing and changing session variables you use the same syntax to access a session variable as for other types of variables. However, you must lock any code that accesses or changes session variables. For example, to display the number of items in ...

Page 332

332 chapter 15: using persistent data and locking because each application scope variable is shared in memory by all requests in the application, these variables can become bottlenecks if used inappropriately. Whenever a request is reading or writing an application scope variable, any other requests...

Page 334

334 chapter 15: using persistent data and locking sample locking scenarios the following examples present scenarios in which you need to lock coldfusion code. These scenarios show only two of the circumstances where locking is vital. Reading and writing a shared variable if you have an application-w...

Page 336

336 chapter 15: using persistent data and locking lock types the cflock tag offers two modes of locking, specified by the type attribute: • exclusive locks (the default lock type) allow only one request to process the locked code. No other requests can run code inside the tag while a request has an ...

Page 338

338 chapter 15: using persistent data and locking considering lock granularity when you design your locking strategy, consider whether you should have multiple locks containing small amounts of code or few locks with larger blocks of code. There is no simple rule for making such a decision, and you ...

Page 340

340 chapter 15: using persistent data and locking ... Examples of cflock the following examples show how to use cflock blocks in a variety of situations. Example with application, server, and session variables this example shows how you can use cflock to guarantee the consistency of data updates to ...

Page 342

342 chapter 15: using persistent data and locking red white blue turquoise black forest green small medium large xlarge note: in this simple example, the application.Cfm page displays the application.Number variable value. Because the application.Cfm file is processed before any code on each coldfus...

Page 344

344 chapter 15: using persistent data and locking.

Page 346

346 chapter 16: securing applications coldfusion security features coldfusion provides scalable, granular security for building and deploying your coldfusion applications. Coldfusion provides the following types of security resources: • development coldfusion mx administrator is protected by a passw...

Page 348

348 chapter 16: securing applications about user security user security lets your application use security rules to determine what it displays. It has two elements: • authentication ensures that a valid user is logged-in, based on an id and password provided by the user. Coldfusion (or, in some case...

Page 350

350 chapter 16: securing applications authenticating users you can use either, or both, of the following forms of authentication to secure your coldfusion application: • web server authentication, where the web server authenticates the user and does not allow access to the website by users without v...

Page 352

352 chapter 16: securing applications if you do not enable the session scope, the authentication information is not kept in a persistent scope. Instead, the detailed login information is put in a memory-only cookie (cfauthorization_applicationname) with a base64-encoded string that contains the user...

Page 354

354 chapter 16: securing applications the cflogin structure provides a consistent interface for determining the user’s login id and password, independent of the technique you use for displaying the login form. Caution: login forms send the username and password without encryption. Basic http authent...

Page 356

356 chapter 16: securing applications an application authentication security scenario an application that does its own authentication might work as follows. The example in “application-based user security example” on page 360 implements this scenario. 1 whenever coldfusion receives a request for a c...

Page 358

358 chapter 16: securing applications implementing user security the following sections provide several examples of ways to implement security using basic authentication and application authentication. Web-server–based authentication user security example the example in this section shows how you mi...

Page 360

360 chapter 16: securing applications reviewing the code the following table describes the securitytest.Cfm page cfml code and its function: application-based user security example the example in this section shows how you might implement user security by authenticating users and then allowing users...

Page 362

362 chapter 16: securing applications the following table describes the cfml code in application.Cfm and its function: . Code description sessionmanagement="yes" > loginstorage=”session” identifies the application, enables the session scope, and enables storing login information in the session scope...

Page 364

364 chapter 16: securing applications reviewing the code the following table describes the loginform.Cfm page cfml code and its function: example: securitytest.Cfm the securitytest.Cfm page shows how any application page can use coldfusion user authorization features. Application.Cfm ensures the exi...

Page 366

366 chapter 16: securing applications using an ldap directory for security information ldap directories are often used to store security information. The following example of an application.Cfm page with a cflogin tag checks an ldap directory to authenticate the user and retrieve the user’s roles. T...

Page 368

368 chapter 16: securing applications reviewing the code the following table describes the code and its function. Comments and some tab characters have been removed for brevity. Code description (uid=#cflogin.Name#))"> manager"> starts the cflogin tag body. Sets several of the values used as attribu...

Page 370

370 chapter 16: securing applications.

Page 372

372 chapter 17: developing globalized applications introduction to globalization globalization lets you create applications for all of your customers in all the languages that you support. In some cases, globalization can let you accept data input using a different character set than the one you use...

Page 374

374 chapter 17: developing globalized applications a locale identifies the exact language and cultural settings for a user. The locale controls how dates and currencies are formatted, how to display time, and how to display numeric data. For example, the locale english (us) determines that a currenc...

Page 376

376 chapter 17: developing globalized applications similar issues can arise if you convert between other character encodings; for example, if you read files encoded in the japanese windows default encoding and display them using shift-jis. To prevent these problems, ensure that the display encoding ...

Page 378

378 chapter 17: developing globalized applications the default language of a website might be different from that of the person connecting to it. For example, you could connect to an english website from a french computer. When coldfusion generates a response, the response must be formatted in the w...

Page 380

380 chapter 17: developing globalized applications tags and functions for controlling character encoding the following tags and functions let you specify the character encoding of text that coldfusion generates and interprets: tag or function attribute or parameter use cfprocessingdirective pageenco...

Page 382

382 chapter 17: developing globalized applications format the date part of a date/time value using the locale convention. Index = "locale" delimiters = ","> #locale# #lsdateformat(now(), "mmm-dd-yyyy")# #lsdateformat(now(), "mmmm d, yyyy")# #lsdateformat(now(), "mm/dd/yyyy")# #lsdateformat(now(), "d...

Page 384

384 chapter 17: developing globalized applications handling url strings url requests to a server often contain name/value pairs as part of the request. For example, the following url contains name/value pairs as part of the url: http://company.Com/prod_page.Cfm?Name=stephen;id=7645 as discussed prev...

Page 386

386 chapter 17: developing globalized applications database administrators configure data sources and usually are required to specify the character encodings for character column data. Many of the major vendors, such as oracle, sybase, and informix, support storing character data in many character e...

Page 388

388 chapter 17: developing globalized applications.

Page 390

390 chapter 18: debugging and troubleshooting applications configuring debugging in the coldfusion mx administrator coldfusion can provide important debugging information for every application page requested by a browser. The coldfusion mx administrator lets you specify which debugging information t...

Page 392

392 chapter 18: debugging and troubleshooting applications debugging ip addresses page by default, when you enable debugging output, the output is visible only to local users (that is, via ip address 127.0.0.1). You can specify additional ip addresses whose users can see debugging output, or even di...

Page 394

394 chapter 18: debugging and troubleshooting applications execution time the execution time section displays the time required to process the request. It displays information about the time required to process all pages required for the request, including the application.Cfm and onrequestend.Cfm pa...

Page 396

396 chapter 18: debugging and troubleshooting applications • coldfusion took 125 ms for processing that was not associated with a specific page. • the total processing time was 328 milliseconds, the sum of 125 + 203. Database activity in the administrator, when database activity is selected on the d...

Page 398

398 chapter 18: debugging and troubleshooting applications the exception information includes information about any application exceptions that are caught and handled by your application code or by coldfusion mx. Exceptions represent events that disrupt the normal flow of an application. You should ...

Page 400

400 chapter 18: debugging and troubleshooting applications controlling debugging information in cfml the following sections describe how you can use cfml tags and functions to display or hide debugging and tracing information. Generating debugging information for an individual query in the administr...

Page 402

402 chapter 18: debugging and troubleshooting applications • in-line in your application page when you specify the inline attribute in a cftrace tag, coldfusion displays the trace output on the page at the cftrace tag location . ( an inline cftrace tag does not display any output if it is inside a c...

Page 404

404 chapter 18: debugging and troubleshooting applications • if a page has many nested cfif and cfelseif tags you can put cftrace tags in each conditional block to trace the execution flow. When you do this, you should use the condition variable in the message or var attribute. • if you find that th...

Page 406

406 chapter 18: debugging and troubleshooting applications you can run the code compatibility analyzer from the coldfusion mx administrator. Select code analyzer from the list of debugging & logging pages. Note: the cfml analyzer does not execute the pages that it checks. Therefore, it cannot detect...

Page 408

408 chapter 18: debugging and troubleshooting applications.

Page 411: Chapter 19

411 chapter 19 introduction to databases and sql coldfusion mx lets you create dynamic applications to access and modify data stored in a database. You do not need a thorough knowledge of databases to develop coldfusion applications, but you must know some basic concepts and techniques. This chapter...

Page 413

What is a database? 413 to access the table to read or modify table data, you use the sql programming language. For example, the following sql statement returns all rows from the table where the department id is 3: select * from employees where deptid=3 note: in this chapter, sql keywords and syntax...

Page 415

Using sql 415 database design guidelines from this basic description, the following database design rules emerge: • each record should contain a unique identifier as the primary key such as an employee id, a part number, or a customer number. The primary key is typically the column used to maintain ...

Page 417

Using sql 417 case sensitivity with databases coldfusion mx is a case-insensitive programming environment. Case insensitivity means the following statements are equivalent: however, many databases, especially unix databases, are case-sensitive. Case sensitivity means that you must match exactly the ...

Page 419

Using sql 419 filtering results the select statement lets you filter the results of a query to return only those records that meet specific criteria. For example, if you want to access all database records for employees in department 3, you use the following query: select * from employees where dept...

Page 421

Using sql 421 where: • column_names specifies a comma-separated list of columns. • value_list specifies a comma-separated list of values. The order of values has to correspond to the order that you specified column names. Note: there are additional options to insert depending on your database. For a...

Page 423

Writing queries using an editor 423 the simple recordset dialog box appears: 4 complete the dialog box. 5 click the test button to execute the query and ensure that it retrieves the information you intended. If you defined a filter that uses parameters input by users, the test button displays the te...

Page 425

Writing queries using an editor 425 the sql builder interface the following figure shows the sql builder interface: the sql builder is divided into the following four sections: writing sql statements sql builder opens a select statement by default, since this is the most common type of query. Sql bu...

Page 427: Chapter 20

427 chapter 20 accessing and retrieving data this chapter describes how to retrieve data from a database and work with query data. This chapter also shows how to use the cfquery tag to query a data source, and use the cfoutput tag to output the query results to a web page. Contents working with dyna...

Page 429

Retrieving data 429 the cfquery tag the cfquery tag is one of the most frequently used cfml tags. You use it with the cfoutput tag to retrieve and reference the data returned from a query. When coldfusion encounters a cfquery tag on a page, it does the following: • connects to the specified data sou...

Page 431

Outputting query data 431 coldfusion creates the emplist data set, but only html and text return to the browser. When you view the page’s source, you see only html tags and the heading “employee list.” to display the data set on the page, you must code tags and variables to output the data. Reviewin...

Page 433

Getting information about query results 433 query output notes and considerations when outputting query results, keep the following guidelines in mind: • a cfquery must precede the cfoutput that references its results. Both must be on the same page (unless you use the cfinclude tag; for more informa...

Page 435

Enhancing security with cfqueryparam 435 • do not use the cfoutput tag query attribute when you output the recordcount or columnlist property. If you do, you get one copy of the output for each row. Instead, prefix the variable with the name of the query. Enhancing security with cfqueryparam some db...

Page 437: Chapter 21

437 chapter 21 updating your database this chapter describes how to use coldfusion to insert, update, and delete information in a database. Contents about updating your datasbase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438 inserting data . . . . ...

Page 439

Inserting data 439 to create an insert form: 1 create a coldfusion page with the following content: value="clear form"> 2 save the file as insert_form.Cfm in the myapps directory under your web_root and view it in your web browser. Note: the form will not work until you write an action page for it. ...

Page 441

Inserting data 441 reviewing the code the following table describes the code and its function: note: if you use form variables in cfinsert or cfupdate tags, coldfusion automatically validates any form data it sends to numeric, date, or time database columns. You can use the hidden field validation f...

Page 443

Updating data 443 creating an update form the following are the key differences between an update form and an insert form: • an update form contains a reference to the primary key of the record that is being updated. A primary key is a field(s) in a database table that uniquely identifies each recor...

Page 445

Updating data 445 creating an action page to update data you can create an action page to update data with either the cfupdate tag or cfquery with the update statement. Creating an update action page with cfupdate the cfupdate tag is the easiest way to handle simple updates from a front-end form. Th...

Page 447

Updating data 447 reviewing the code the following table describes the code and its function: creating an update action page with cfquery for more complicated updates, you can use a sql update statement in a cfquery tag instead of a cfupdate tag. The sql update statement is more flexible for complic...

Page 449

Deleting data 449 to delete one record from a database: 1 in update_form.Cfm, change the title to “delete form” and the text on the submit button to “delete record”. 2 change the form tag so that it appears as follows: 3 save the modified file as delete_form.Cfm. 4 create a coldfusion page with the ...

Page 451: Chapter 22

451 chapter 22 using query of queries a query that retrieves data from a record set is called a query of queries. After you generate a record set, you can interact with its results as if they were database tables by using query of queries. This chapter describes the benefits and procedures for this ...

Page 453

About record sets 453 creating a record set with a function in addition to creating a record set by using a cfquery or other cfml tags, you can create it with the querynew () function. To create a record set with the querynew() function: 1 create a coldfusion page with the following content: years_p...

Page 455

About query of queries 455 • you can obtain drill-down, master-detail information for which you do not access the database for the details. For example, you can select information about departments and employees in a query, and cache the results. You can then display the employees’ names. When users...

Page 457

About query of queries 457 reviewing the code the master query retrieves the entire employee table from the companyinfo data source (the companyinfo database). The detail query selects only the three columns to display for employees with the specified last name. The following table describes the cod...

Page 459

About query of queries 459 maxrows)#">see next #maxrows# rows 2 save the page as qoq_next_row.Cfm in the myapps directory under the web_root . 3 in your web browser, enter the following url to display the query results: http://127.0.0.1/myapps/qoq_next_row.Cfm the following figure shows how the outp...

Page 461

About query of queries 461 the first cfdump tag shows the master query, which retrieves all records. The second cfdump shows the query of queries results. Tip: adjust the score criterion of the detail query to reflect the contents of your collection. The next example shows how a query of queries com...

Page 463

Query of queries user guide 463 coldfusion supports inner joins between two tables, as the following example shows. This operation is the most common type of join. Select dog_id, breed_id from dogs, breed where dogs.Dog_id = breed.Dog_id; using unions the union operator lets you combine the results ...

Page 465

Query of queries user guide 465 union select * from tablec in the first statement, there are no duplicates in the union between tableb and tablec. Then, in the union between that set and tablea, the all keyword includes the duplicates. In the second statement, duplicates are included in the union be...

Page 467

Query of queries user guide 467 like conditional this conditional lets you perform wildcard searches, in which you compare your data to search patterns. This strategy differs from other conditionals, such as between or in, because the like conditional compares your data to a value that is partially ...

Page 469

Query of queries user guide 469 example the following example uses the avg() function to retrieve the average iq of all terriers: select dog_name, avg(dog_iq) as avg_iq from dogs where breed like '%terrier'; arbitrary expressions in aggregate functions coldfusion supports aggregate functions of any ...

Page 471

Query of queries user guide 471 having example select (lorange+hirange)/2 as x, count(*) from roysched group by x having x > 10000 handling null values coldfusion uses boolean logic to handle conditional expressions. Proper handling of null values requires the use of ternary logic. The is [not] null...

Page 473

Query of queries user guide 473 using queries of queries with numeric dates if you create a query object with querynew() and populate a column with dates in numeric format (for example, 12/24/02), the dates are preserved as a string inside the query object until a query of queries is applied to the ...

Page 475

Bnf for query of queries 475 null_cond ::= row_constructor ( )? Comparison_cond ::= row_constructor comparison_operator row_constructor between_cond ::= row_constructor ( )? Row_constructor row_constructor in_cond ::= row_constructor ( )? ( expression_list ) row_constructor ::= expression comparison...

Page 477: Chapter 23