ORA-12991: column is referenced in a multi-column constraint ORA-12991 means that the column you want to drop is bound to some multi-column constraints. You must… Read More »How to Resolve ORA-12991 Error Message
Modify Primary Key Sometimes, developers may design a better primary key to support the uniqueness of a table and they want to replace the current… Read More »How to Alter Primary Key in Oracle
Add Primary Key There're 3 basic ways to create a primary key for a table. 1. System-Generated Name You don't have to provide a name… Read More »How to Add Primary Key in Oracle
For getting the information of a primary key, we have to join two dictionary views, one is ALL_CONS_COLUMNS, the other is ALL_CONSTRAINTS. And then we… Read More »How to Check Primary Key in Oracle