Constraint

How to Resolve ORA-02449: unique/primary keys in table referenced by foreign keys

by Ed Chen
April 27, 2023May 25, 2023

ORA-02449 Tried to drop a table, but it failed with ORA-02449. SQL> show user USER is "HR" SQL> drop table employees; drop table employees … Read More »

How to Find References to Table

by Ed Chen
April 26, 2023April 28, 2023

Referential Integrity To check the referential relationship of a table in details, we have to join some dictionary views, ALL_CONSTRAINTS and ALL_CONS_COLUMNS. For example, we'd… Read More »

How to Resolve ORA-01981: CASCADE CONSTRAINTS must be specified to perform this revoke

by Ed Chen
December 1, 2022March 16, 2023

ORA-01981 Tried to revoke object privileges from an user, but it failed with ORA-01981. SQL> revoke all on HR.EMPLOYEES from OE revoke all on HR.EMPLOYEES… Read More »

How Oracle Rename Constraint

by Ed Chen
October 19, 2022November 17, 2022

ALTER TABLE RENAME CONSTRAINT To rename a constraint, we need to do it through ALTER TABLE. Let's see a constraint. SQL> show user USER is… Read More »

How to Resolve ORA-02266: unique/primary keys in table referenced by enabled foreign keys

by Ed Chen
December 17, 2016May 25, 2023

ORA-02266 ORA-02266 means that you can't truncate the table because reference keys constraint still depend on the data of the table. Truncate a Single Table… Read More »

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