The Cfquery Tag; The Cfquery Tag Syntax - MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX Develop Manual

The cfquery tag

The tag is one of the most frequently used CFML tags. You use it with the
cfquery
to retrieve and reference the data returned from a query. When ColdFusion encounters a
tag on a page, it does the following:
•
Connects to the specified data source.
•
Performs SQL commands that are enclosed within the block.
•
Returns result set values to the page in a query object.

The cfquery tag syntax

The following code shows the syntax for the
<cfquery name="EmpList" datasource="CompanyInfo">
SQL code...
</cfquery>
In this example, the query code tells ColdFusion to do the following:
•
Connect to the CompanyInfo data source (the company.mdb database).
•
Execute SQL code that you specify.
•
Store the retrieved data in the query object EmpList.
When creating queries to retrieve data, keep the following guidelines in mind:
•
You must use opening
block tag.
•
Enter the query
•
To tell the database what to process during the query, place SQL statements inside the
block.
•
When referencing text literals in SQL, use single quotation marks ('). For example,
FROM mytable WHERE FirstName='Jacob'
first name is Jacob.
•
Surround attribute values with double quotation marks ("attrib_value").
•
Make sure that a data source exists in the ColdFusion MX Administrator before you reference
it in a
cfquery
•
Columns and tables that you refer to in your SQL statement must exist, otherwise the query
will fail.
•
Reference the query data by naming the query in one of the presentation tags, such as
,
cfoutput cfgrid
•
When ColdFusion returns database columns, it removes table and owner prefixes. For
example, if you query Employee.Emp_ID in the query, the Employee, is removed and returns
as Emp_ID. You can use an alias to handle duplicate column names; for more information, see
Chapter 22, "Using Query of Queries," on page
•
You cannot use SQL reserved words, such as MIN, MAX, COUNT, in a SQL statement.
Because reserved words are database-dependent, see your database's documentation for a list of
reserved words.
and ending
<cfquery>
and
name datasource
tag.
, ,
cftable cfgraph
tag:
cfquery
tags, because the
</cfquery>
attributes within the opening
selects every record from mytable in which the
, or later on the page.
cftree
451.
tag
cfoutput
cfquery
tag is a
cfquery
tag.
cfquery
cfquery
SELECT *
Retrieving data 429