Tag: Cascade

Oracle – PL-SQL – Foreign key on delete cascade

Oracle, Oracle-Tips and Tricks, Varinder Sandhu

ON DELETE CASCADE: When a referenced parent table row is removed the entire child are removed automatically. Example: — Create a Table as mytable1 having the PRIMARY KEY CREATE TABLE MYTABLE1 ( ID INTEGER PRIMARY KEY, EMP_NAME VARCHAR2(10) ); — Create a Table as mytable2 having the FOREIGN KEY CREATE TABLE MYTABLE2 ( ID INTEGER, ADDRESS VARCHAR2(50), FOREIGN KEY (ID) REFERENCES MYTABLE1 (ID) ON DELETE CASCADE ); — Insert one row in mytable1 INSERT INTO MYTABLE1 (ID, EMP_NAME) VALUES (1,'VARINDER');

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Oracle – Drop User Cascade

Oracle, Oracle-Tips and Tricks, Varinder Sandhu

If you have user that owns objects and you want to drop the user then you have to use the Cascade keyword with your drop statement/command. The Oracle DROP USER CASCADE command drops a user and all owned objects. Without using DROP USER CASCADE you cannot delete the user that owns objects. Example: First you try to drop the user without CASCADE then below error occurred because my_user user own the my_table object (as shown above) But now use the

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