The am_delete purpose function

The database server calls am_delete for:

A DELETE statement
An UPDATE statement that requires a change in physical location
An ALTER FRAGMENT statement that moves a row to a different fragment
A MERGE statement, which can perform both INSERT and DELETE or UPDATE operations on the result of an outer join of two tables

Syntax

mi_integer am_delete(MI_AM_TABLE_DESC *tableDesc,
   MI_ROW *row,
   MI_AM_ROWID_DESC *ridDesc)

tableDesc: Points to the index descriptor.
row: Points to a row structure that contains the key value to delete.
ridDesc: Points to the row-ID descriptor.

Usage

The am_delete deletes one index key in the virtual index. Additionally, the function passes (by reference) the row-ID descriptor, which contains the location of the underlying table row to delete.

In response to a DELETE statement, the database server first calls the appropriate purpose functions to scan for the index entry or entries that qualify for deletion and then executes am_delete separately for each qualifying entry.

The access method identifies and executes support functions to adjust the index structure after the delete.

Important: The database server does not call the am_delete purpose function unless you set both the am_rowids and am_readwrite purpose flags.

Important: If the access method does not supply an am_delete purpose function, but an SQL statement requires it, the database server raises an error. For more information on how to handle this error, see Supply error messages and a user guide for your functions.

For more information, see the purpose flags am_rowids and am_readwrite in Setting purpose functions, flags, and values.

Return values

MI_OK: Indicates success.
MI_ERROR: Indicates failure.