Notes on Parameters

Enabling the use of User-Defined Parameters

For batch-mode AQT, User-defined Parameters are always enabled.

For online AQT, User-defined Parameters are (by default) not enabled. You can enable this by selecting Enable Parameters in the Parameters dialog. Click on OK. This setting is saved between sessions, so you only have to do this once.

Parameter Character

On the Parameters window, you can specify whether parameters are to be indicated with a $ or a colon. This is done with the Indicate parameters with option. By default, this will be a $. The only choices are $ or colon.

Parameter Replacement

• There is no end-delimiter for the parameters. Parameter replacement is "dumb". AQT just replaces the $ + parameter name with the parameter value. If you have a parameter called cust (with value SMITH) and a parameter called custcode (with value JONES) then $custcode will be substituted as SMITHcode.

  You can avoid this by having fuller names for parameters - for example: custname, custcode, custid, custcountry etc rather than just cust.

• If a parameter is not found, it will not be replaced. You will not get a warning.
• Parameter names are case independent (so $cust and $Cust are equivalent).
• If you want to see what your SQL looks like after the parameters have been replaced, from the Run SQL window go Parameters > Show SQL after parameter replacement

Saving Parameter values

If Options > General > Remember user-parms between sessions is selected, AQT will save the parameter values between sessions.

The file they are saved in is parms.txt in your Default Directory. The parms are saved whenever AQT shuts down successfully, or when OK is clicked on the User-Defined Parameters window.

Parameters are often used when running batch scripts. Any changes to parameters done during batch scripts are not saved.

Referencing Another User-Defined Parameter

A parameter can reference parameter.

Example:

In this, the value of rundate is the name of another parameter.

When you specify:

select * from accounts where transaction_date > '$rundate'

the following will be run:

select * from accounts where transaction_date > '2007-03-31'

Using the function Parameters > Show SQL after parameter replacement is useful for seeing how parameters will be resolved.

Deleting Parameters

You can delete parameters with the delparm statement. You might wish to do this at the start of a batch script. Examples:

--aqt delparm,parm=custcode (deletes a single parameter)

--aqt delparm,parm=*cust* (deletes all parms containing cust)

--aqt delparm,parm=* (deletes all parameters)