MACROMEDIA ColdFusion MX, Руководство по разработке

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Strings 63
When you reference query columns inside tags, such as
cfoutput
and
cfloop
, in which you
specify the query name in a tag attribute, you do not have to specify the query name.
You can access query columns as if they are one-dimensional arrays. For example, the following
line assigns the contents of the Employee column in the second row of the myQuery query to the
variable myVar:
<cfset myVar = myQuery.Employee[2]>
Note: You cannot use array notation to refer to a row (of all columns) of a query. For example,
myQuery[2] does not refer to the second row of the myQuery query object.
Working with structures and queries
Because structure variables and query variables are references to objects, the rules in the following
sections apply to both types of data.
Multiple references to an object
When multiple variables refer to a structure or query object, the object continues to exist as long
as at least one reference to the object exists. The following example shows how this works:
<cfscript> depts = structnew();</cfscript>
<cfset newStructure=depts>
<cfset depts.John="Sales">
<cfset depts=0>
<cfoutput>
#newStructure.John#<br>
#depts#
</cfoutput>
This example displays the following output:
Sales
0
After the
<cfset depts=0>
tag executes, the depts variable does not refer to a structure; it is a
simple variable with the value 0. However, the variable newStructure still refers to the original
structure object.
Assigning objects to scopes
You can give a query or structure a different scope by assigning it to a new variable in the other
scope. For example, the following line creates a server variable, Server.SScopeQuery, using the
local myquery variable:
<cfset Server.SScopeQuery = myquery>
To clear the server scope query variable, reassign the query object, as follows:
<cfset Server.SScopeQuery = 0>
This deletes the reference to the object from the server scope, but does not remove any other
references that might exist.
Copying and duplicating objects
You can use the
Duplicate
function to make a true copy of a structure or query object. Changes
to the copy do not affect the original.