ALL_CONSTRAINTS

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-12991 Error Message

by Ed Chen
April 25, 2020December 20, 2022

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 Check Primary Key in Oracle

by Ed Chen
April 15, 2020December 10, 2022

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 Oracle Add NOT NULL Constraint

by Ed Chen
November 23, 2019December 10, 2022

Add NOT NULL Constraint As I mentioned in resolving ORA-00904 for adding a constraint, NOT NULL is a constraint, but it's more like an attribute… 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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