Purpose-function syntax
The database server expects a particular prototype for each purpose function. As the access-method developer, you program the actions of a purpose function but must use the parameters and return values that the Virtual-Table Interface (VTI) prototypes specify.
For each purpose function that your access method provides, use the prototype that the topics in this section show, but change the prototype-function name to a unique name. For example, you might save your version of am_open with the name vtable_open(). To associate the unique purpose-function names to the corresponding prototype names, use the CREATE PRIMARYACCESS_METHOD statement, as The CREATE ACCESS_METHOD (+) statement specifies.
The parameter list for each purpose function includes (by reference) one or more descriptor data structures that describe the SQL statement keywords or oncheck options and the specified table that requires the access method.
Purpose functions are entry points from which the access method calls other routines from the access-method library, DataBlade® API functions, and the VTI functions that Accessor functions describes.
This section lists purpose-function prototypes in alphabetical order.