Plsql trigger if updating: NEW.c1); -- Previously, we couldn't change the new value for a LOB.Oracle Database executes all triggers of the same type before executing triggers of a different type.If you have multiple triggers of the same type on a single table, then Oracle Database chooses an arbitrary order to execute these triggers.A trigger is a pl/sql block structure which is fired when a DML statements like Insert, Delete, Update is executed on a database table.A trigger is triggered automatically when an associated DML statement is executed.This type of trigger also provides an additional correlation name for accessing the parent row that contains the nested table being modified. -- Now, we can replace it, or construct a new value using SUBSTR, INSTR...
A relational database does not guarantee the order of rows processed by a SQL statement.
Because the trigger uses the clause, it might be executed multiple times, such as when updating or deleting multiple rows.
You might omit this clause if you just want to record the fact that the operation occurred, but not examine the data for each row.
For Example: The price of a product changes constantly.
It is important to maintain the history of the prices of the products.