Designing and coding the IP : DDL object management : Drop Table processing

Drop Table processing

The SQL syntax to drop a table is:

DROP TABLE table-name [drop-option];

drop-option = CASCADE | RESTRICT

When a SQL query of this form is issued, OpenAccess SDK SQL engine maps this information to a list of schema objects of type damobj_table. When the DDL function in the IP is called, the DDL function should perform the following steps:

1. Get information about the table (name, owner, qualifier)

pList = dam_getSchemaObjectList(hstmt, DAMOBJ_TYPE_TABLE);

damobj_table pTableObj = getFirstSchemaObject(pList);

2. Get foreign keys information to check the optional drop-option in the delete_rule (DAM_CASCADE | DAM_RESTRICT).

pList = dam_getSchemaObjectList(hstmt, DAMOBJ_TYPE_FKEY);

damobj_stat pFkeyObj = getFirstSchemaObject(pList);

3. Use this information to drop the table.