Parameter mapping is the key component of a procedure's definition. Parameter mapping links the attributes or fields in your host application model with parameters in your procedure, which are then used by the procedure to select, update, insert, or delete host data.
The type of parameter you choose to map is dependent on the type of procedure you are creating. The Tables dialog box and Procedure Editor provide different options.
There are three types of parameters:
|Filter parameter||Identify the records you want to select, update, or delete.|
|Output parameter||Contain data that is to be returned from the select procedure.|
|Data parameter||Fields or attributes to update or insert.|
|Select||A filter parameter to identify the records to select and output parameters that return the requested data|
|Update||A filter parameter to identify the records to update and data parameters that identify the attributes and/or fields to be updated.|
|Insert||Data parameters that identify the attributes and/or fields that are inserted.|
|Delete||A filter parameter to identify the records to delete.|
There are two circumstances where you may want to use special mapping options:
To solve these situations:
Comparing parameters to recordset fields enables you to perform finely detailed filtering of data that a procedure retrieves from a recordset. This makes it possible to create complex procedure logic capable of sophisticated data manipulation. Only the records that satisfy all comparison mappings are retrieved.
These instructions assume that you have already inserted the recordset. If you have not done so, follow the instructions on inserting a recordset into a procedure.
To compare a filter parameter to a recordset field for a SELECT procedure:
When the procedure runs, the parameter is compared to the data retrieved from the recordset; only the data matching all the compare filters is returned to the querying application.
In some cases, a filter parameter you use to retrieve host data is not itself available as an attribute or recordset field that can be returned to a querying application. To solve this problem, you can map a filter parameter to an output parameter.
To map a filter parameter to an output parameter: