Calling Stored Procedures

Stored procedures can be called in several different ways with wwSQL. You can use either syntax that uses the AddParameter() method to add parameters to add named parameters to your SQL queries or you can use standard VFP SQL Passthrough syntax using ?varname in a string.

Using the AddSqlParameters() is the preferred mechanism however, since it ensures that the parameter values you are passing are actually in scope when the method is executed as the values are copied into an internal array. Otherwise if you're using ?varname syntax make sure the variables you use are PRIVATE so they are visible inside of the wwSql method that executes the query.

Let's take the following dummy stored procedure:

  @cName varchar(30),
  @iResult int OUTPUT

select * from wws_customers where company like @cName

Set @iResult = 10

This SP takes a couple of parameters one of which is an output parameter and it returns a result cursor.

The official way to do this is the following syntax:


*** Add named parameters
oSQL.AddParameter(0,"iResult","OUT")  && Output parameter

*** Make the SP call against the server
IF !oSQL.ExecuteStoredProcedure("test")
      ? oSQL.cErrorMsg

*** Retrieve a parameter
lnResultValue = oSQL.oParameters["iResult"].Value

*** Cursor returned from the SELECT

The above is the most effective way and gives you the most control over parameter types. You can actually specify each parameters type and width, size etc.

Using traditional VFP SQL Passthrough Syntax

We recommend you use the above syntax but for backwards compatibility you can also use Visual FoxPro SQL Passthrough syntax with Execute or ExecuteNonQuery when using wwSQL.

cName = "W%"
iResult = 0
oSQL.Execute("execute Test ?cName,?@iResult")

*** Retrieve parameters
? iResult
? o.Parameters["iResult"].Value

Note the @iResult parameter in the SQL string, which signifies that he parameter is an OUT parameter.

© West Wind Technologies, 2023 • Updated: 11/08/18
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