Difference between revisions of "AQUERY"
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Revision as of 17:10, 1 August 2009
Contents
Description
This function will queue up a query and run it asynchronously in a background thread (rather than the script waiting for it to complete like the QUERY function). Once the query has been executed, a specified callback function will run.
Unlike the QUERY function, results are not stored in the ROW object. Instead they are passed in to the callback function as LOCALs. The following table shows the differences between accessing the results for the two functions:
| QUERY | AQUERY |
| ROW.NUMROWS | LOCAL.NUMROWS |
| ROW.NUMCOLS | LOCAL.NUMCOLS |
| ROW.row_index.col_index | LOCAL.row_index.col_index |
| ROW.row_index.col_name | LOCAL.row_index.col_name |
Note 1: An open database connection is required for this function to work correctly. See the CONNECT function for information regarding the opening of a database connection.
Note 2: The AQUERY and QUERY functions are intended to run SQL commands that return results (such as SELECT). For commands that do not return results consider using the AEXECUTE and EXECUTE functions.
Valid for the following objects:
Syntax
AQUERY function, command
| Argument | Type | Description | ||||||||
| function | string | A script function to call when the command has been executed.
| ||||||||
| command | string | The SQL command to execute. |
Return Values
This function returns one of two values when executed. See the table below for the meanings of the return values:
| Return Value | Description |
| 0 | Command has not been successfully queued. |
| 1 | Command has been successfully queued. |
Examples
//
// Queues an SQL query.
//
[FUNCTION f_aquery]
SERV.LOG Selecting some values in the background.
IF (<DB.AQUERY f_aquery_callback, SELECT 10 AS test1, 20 AS test2, 30 AS test3> == 0)
SERV.LOG Failed to queue command.
ELSE
SERV.LOG Command queued.
ENDIF
RETURN
//
// This function will be called when the query has been executed.
//
[FUNCTION f_aquery_callback]
IF (<ARGN2> == 0)
SERV.LOG The command failed to execute. (<ARGS>)
ELSE
SERV.LOG The command succeeded, <dLOCAL.NUMROWS> row(s) of data returned. (<ARGS>)
FOR 0 <EVAL <LOCAL.NUMROWS> - 1>
SERV.LOG #<EVAL <LOCAL._FOR> + 1>. <LOCAL.<dLOCAL._FOR>.test1>, <LOCAL.<dLOCAL._FOR>.test2>, <LOCAL.<dLOCAL._FOR>.test3>
ENDFOR
ENDIF
RETURN
