Oracle trigger where clause updating

A trigger may be specified to fire whenever a DELETE, INSERT, or UPDATE of a particular database table occurs, or whenever an UPDATE occurs on on one or more specified columns of a table.At this time SQLite supports only FOR EACH ROW triggers, not FOR EACH STATEMENT triggers.Both the WHEN clause and the trigger actions may access elements of the row being inserted, deleted or updated using references of the form "NEW.column-name" and "OLD.column-name", where column-name is the name of a column from the table that the trigger is associated with.OLD and NEW references may only be used in triggers on events for which they are relevant, as follows: If a WHEN clause is supplied, the SQL statements specified are only executed if the WHEN clause is true.Hence explicitly specifying FOR EACH ROW is optional.

When RAISE(IGNORE) is called, the remainder of the current trigger program, the statement that caused the trigger program to execute and any subsequent trigger programs that would have been executed are abandoned. If the statement that caused the trigger program to execute is itself part of a trigger program, then that trigger program resumes execution at the beginning of the next step.Because of the behaviors described above, programmers are encouraged to prefer AFTER triggers over BEFORE triggers.A special SQL function RAISE() may be used within a trigger-program, with the following syntax raise-function: When one of RAISE(ROLLBACK,...), RAISE(ABORT,...) or RAISE(FAIL,...) is called during trigger-program execution, the specified ON CONFLICT processing is performed the current query terminates.Furthermore, if a BEFORE trigger modifies or deletes a row, then it is undefined whether or not AFTER triggers that would have otherwise run on those rows will in fact run.The value of NEW.rowid is undefined in a BEFORE INSERT trigger in which the rowid is not explicitly set to an integer.

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