Primary Key

How to Resolve ORA-02429: cannot drop index used for enforcement of unique/primary key

by Ed Chen
April 29, 2020May 6, 2020

ORA-02429 ORA-02429 means that the index you want to drop is a primary key. SQL> drop index hr.JHIST_EMP_ID_ST_DATE_PK; drop index hr.JHIST_EMP_ID_ST_DATE_PK … Read More »

ORA-12991: column is referenced in a multi-column constraint

by Ed Chen
April 25, 2020May 6, 2020

ORA-12991 ORA-12991 means that the column you want to drop is bound to some multi-column constraint. Usually, it's a primary key constraint, but not always.… Read More »

How to Modify Primary Key

by Ed Chen
April 22, 2020May 7, 2020

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 Drop Primary Key

by Ed Chen
April 22, 2020May 7, 2020

Drop Primary Key Primary key is sort of a constraint rather than an index, you should treat it as a constraint first so as to… Read More »

How to Add Primary Key

by Ed Chen
April 22, 2020November 12, 2020

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 Check Primary Key of a Table

by Ed Chen
April 15, 2020November 12, 2020

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 »