A relational database management system (DBMS) from Oracle, which runs on more than 80 platforms. Introduced in the late 1970s, Oracle was the first database product to run on a variety of platforms from micro to mainframe. Starting in 1999 with Version 8

The specific group: ORA Messages

Oracle Exception Messages

The specific error code:

Chosen lang:
ORA-14063Unusable index exists on unique/primary constraint key
Cause:Drop the existing index or rebuild it using ALTER INDEX REBUILD
Action:User attempted to add or enable a primary key/unique constraint on column(s) of a table on which there exists an index marked Index Unusable.