Oracle trigger if inserting or updating

Two popular reasons to use compound trigger are: CREATE OR REPLACE TRIGGER compound_trigger_name FOR [INSERT|DELETE]UPDATE [OF column] ON table COMPOUND TRIGGER -- Declarative Section (optional) -- Variables declared here have firing-statement duration.

--Executed before DML statement BEFORE STATEMENT IS BEGIN NULL; END BEFORE STATEMENT; --Executed before each row change- : NEW, : OLD are available BEFORE EACH ROW IS BEGIN NULL; END BEFORE EACH ROW; --Executed aftereach row change- : NEW, : OLD are available AFTER EACH ROW IS BEGIN NULL; END AFTER EACH ROW; --Executed after DML statement AFTER STATEMENT IS BEGIN NULL; END AFTER STATEMENT; END compound_trigger_name; Hopefully this example with make things more clear. SALARY IS NULL) ) THEN v_index := v_index 1; v_emp_changes(v_index).upd_dt := SYSDATE; v_emp_changes(v_index).upd_by := SYS_CONTEXT ('USERENV', 'SESSION_USER'); v_emp_changes(v_index).emp_id := : NEW.emp_id; v_emp_changes(v_index).field := 'SALARY'; v_emp_changes(v_index).from_value := to_char(: OLD.

The system checks for the violation of the constraints on actions that may cause a violation, and aborts the action accordingly.

oracle trigger if inserting or updating-73

(Before version 2.1, triggers on views deemed updatable would run in addition to the default logic.) Firebird does not raise mutating table exceptions (like Oracle), and triggers will by default both nest and recurse as required (SQL Server allows nesting but not recursion, by default.) Firebird's triggers use NEW and OLD context variables (not Inserted and Deleted tables,) and provide UPDATING, INSERTING, and DELETING flags to indicate the current usage of the trigger.

Database-level triggers can help enforce multi-table constraints, or emulate materialized views.

ALTER TABLE chicken ADD CONSTRAINT chicken REFegg FOREIGN KEY (e ID) REFERENCES egg(e ID) INITIALLY DEFERRED DEFERRABLE; ALTER TABLE egg ADD CONSTRAINT egg REFchicken FOREIGN KEY (c ID) REFERENCES chicken(c ID) INITIALLY DEFERRED DEFERRABLE; In general, Oracle returns an error message when a constraint is violated.

Specifically for users of JDBC, this means an SQLException gets thrown, whereas for Pro*C users the SQLCA struct gets updated to reflect the error.

In Oracle, a sequence object (created by CREATE SEQUENCE statement) is used to generate IDs (auto-increment, identity values).

Last modified 02-Oct-2019 08:30