Selecting from and updating the same table oracle
A database trigger is a stored procedure that automatically executes whenever an event occurs. Oracle initiates an ‘AFTER INSERT’ trigger after an insert event has been occurred and an ‘AFTER UPDATE’ trigger after an update event has been occurred.
CREATE or REPLACE TRIGGER emp_after_insert AFTER INSERT ON emp FOR EACH ROW DECLARE BEGIN insert into emp_backup values (:new.empid, :new.fname, :new.lname); DBMS_OUTPUT.
Object Browser enhancements The Object Browser has a new filter field where you can quickly enter filter expressions to limit the browser contents.You then specify the type of data modification that is to occur when the records between the two data are matched or are not matched. Rate) --When there is a row that exists in target table and --same record does not exist in source table --then delete this record from target table WHEN NOT MATCHED BY SOURCE THEN DELETE --$action specifies a column of type nvarchar(10) --in the OUTPUT clause that returns one of three --values for each row: 'INSERT', 'UPDATE', or 'DELETE', --according to the action that was performed on that row OUTPUT $action, DELETED. MERGE is very useful, especially when it comes to loading data warehouse tables, which can be very large and require specific actions to be taken when rows are or are not present. Rate --When no records are matched, insert --the incoming records from source --table to target table WHEN NOT MATCHED BY TARGET THEN INSERT (Product ID, Product Name, Rate) VALUES (SOURCE. Now before updating ’empid’ column in ’emp’ table see the ’emp’ and ’emp_backup’ table records.Vishwanath Dalvi is a gifted engineer and tech enthusiast. When not hacking around or supporting the open source community, he is trying to overcome his phobia of dogs.