Question

I am writing a schema upgrade script for a product that depends on an Oracle database. In one area, I need to create an index on a table – if that index does not already exist. Is there an easy way to check for the existence of an index that I know the name of in an Oracle script?

It would be similar to this in SQL Server: IF NOT EXISTS (SELECT * FROM SYSINDEXES WHERE NAME = ‘myIndex’) // Then create my myIndex

Answer 1

select count(*) from user_indexes where index_name = ‘myIndex’

sqlplus won’t support IF…, though, so you’ll have to use anonymous PL/SQL blocks, which means EXECUTE IMMEDIATE to do DDL.

DECLARE     i INTEGER; BEGIN     SELECT COUNT(*) INTO i FROM user_indexes WHERE index_name = 'MYINDEX';     IF i = 0 THEN         EXECUTE IMMEDIATE 'CREATE INDEX myIndex ...';     END IF; END; / 

Edit: as pointed out, Oracle stores unquoted object names in all uppercase.