ColdFusion Variables

• CF uses variables to store data in memory.

• There are many different types of variables; each has its own use.

• To use a variable, name it and assign it a value.

Typeless

• All CF variables are typeless, which means you do not need to identify the type of the data(Such as numbers or dates.)

• Behind the scenes CF stores all the values as strings.

• When variables are accessed and expected to be of a certain type they are “cast” into the expected type.

Variable Naming

• Rules– Use one word– Do not use spaces– Begin with a letter– Use only letter, and the underscore– Do not use special characters

Variable Prefixes

• There are many types of variables in CF.

• Each variable has it is own scope– Where it exists– How long it exist for– Where the variable value is stored.

Referencing Variables

• To reference a local variable’s value, use the variables prefix.

• Notice that you reference variables in the expression (right hand side of the equal sign) without using double quotes.

<cfset firstname = “Sue”><cfset lastname=“Smith”><cfset fullname = variables.firstname +

variables.lastname>

CF would attempt to convert FirstName and LastName to numeric values which would result in an error.

<cfset thenum=“40”>

<cfset newnum = variables.thenum+”25”>

<cfset the string = “new number is: variables.newnum>

Creating local variables with <CFSET>

• The <cfset> tag is used to initialize the value of a variable.

• You set the value as being equal to an expression.

• The syntax for this tag is:

<cfset variable_name = expression>

Variables have specific values

<cfset firstname= “Sue”>

<cfset age= “29”>

• All literal values are surrounded by double quotes “Sue” “29”

&

• Here, variable draws its value from two other variables:

<cfset firstname = “Sue”>

<cfset lastname=“Smith”>

<cfset fullname= variables.firstname &” ”& variables.lastname>

&

• The ampersand (&) is a concatenation character and will build the string with the value of FirstName, a space and the value of last name.

• The result would be:

<cfoutput>#variables.fullname#</cfoutput>

• Sue Smith

<CFQUERY>

CFQUERY

CF Functions

• CFML is made up of two primary language elements– Tags – perform operations such as accessing a

database, evaluating a condition

– Functions- Return (possibly process) data and do things such as getting the current date and time, converting text to uppercase, and rounding a number to its nearest integer.

• #Now()# is an instruction telling CF to execute a function named Now()- a function that returns the current date and time.

• What happens – If no pound signs?– If put outside the cfoutput tag?

• Format of that date function is not entirely readable.

• Another function, DateFormat( ) can help here.

• DateFormat () role is to format dates so they are readable.

• DateFormat is an example of a function that accepts (and requires) that data must be passed to it – after all it needs to know which date you want to format to display.

• #DateFormat(Now())# tells CF to format the date returned by the Now() function.

NESTed

• Passing a function as a parameter to another function is referred to as NESTING.

• The Now() function is said to be NESTED in the DateFormat() function.

DateFormat()

• DateFormat() takes second optional attribute: – A format mask used to describe the output format.

#DateFormat(Now(), “MMMM-DD-YY”)#

#DateFormat(Now(), “MM-DD-YY”)#

#DateFormat(Now(), “DDD,MMMM DD-YYYY”)#

Parameters passed to a function are always seperated by comma.

RecordCount

RecordCount contains the total number of records returned by the query.

Number of rows returned:

<cfoutput>

#queryname.recordcount#

</cfoutput>

CurrentRow

<cfoutput query =“queryname”>

Row#queryname.currentrow# of #queryname.recordcount#

</cfoutput>