What are the 12 types of triggers in Oracle?

What are the 12 types of triggers in Oracle?

Trigger Type Combinations

  • BEFORE statement trigger. Before executing the triggering statement, the trigger action is run.
  • BEFORE row trigger.
  • AFTER statement trigger.
  • AFTER row trigger.

How can we create a schema trigger in Oracle?

How to create a trigger in Oracle

  1. 1) CREATE OR REPLACE. The CREATE keyword specifies that you are creating a new trigger.
  2. 2) Trigger name.
  3. 3) BEFORE | AFTER.
  4. 4) ON table_name.
  5. 5) FOR EACH ROW.
  6. 6) ENABLE / DISABLE.
  7. 7) FOLLOWS | PRECEDES another_trigger.

How can we create a schema trigger?

To create a trigger in your own schema on a table in your own schema or on your own schema ( SCHEMA ), you must have the CREATE TRIGGER system privilege. To create a trigger in any schema on a table in any schema, or on another user’s schema ( schema . SCHEMA ), you must have the CREATE ANY TRIGGER system privilege.

What is the level of creating trigger?

Row-level triggers are the most common type of triggers; they are often used in data auditing applications. Row-level trigger is identified by the FOR EACH ROW clause in the CREATE TRIGGER command. Statement-level triggers execute once for each transaction.

What is row level and statement level trigger?

Row level triggers executes once for each and every row in the transaction. Statement level triggers executes only once for each single transaction. Example: If 1500 rows are to be inserted into a table, the statement level trigger would execute only once.

What is statement level trigger in Oracle?

A statement-level trigger is fired whenever a trigger event occurs on a table regardless of how many rows are affected. In other words, a statement-level trigger executes once for each transaction. For example, if you update 1000 rows in a table, then a statement-level trigger on that table would only be executed once.

What is sequence in Oracle 11g?

A sequence is an object in Oracle that is used to generate a number sequence. This can be useful when you need to create a unique number to act as a primary key.

How many types of triggers are there in Oracle?

A single SQL statement can potentially fire up to four types of triggers: BEFORE row triggers, BEFORE statement triggers, AFTER row triggers, and AFTER statement triggers. A triggering statement or a statement within a trigger can cause one or more integrity constraints to be checked.

What is schema trigger?

You can define triggers for the same event (such as SERVERERROR) on both the schema and database levels. Oracle fires the trigger whenever a DROP statement removes an existing database object from the schema. ALTER. Oracle fires the trigger whenever an ALTER statement modifies an existing database object in the schema.

How many times a trigger statement is executed?

Statement level triggers executes only once for each single transaction. Specifically used for data auditing purpose.

What is a row-level trigger?

A row-level trigger fires once for each row that is affected by a triggering event. For example, if deletion is defined as a triggering event for a particular table, and a single DELETE statement deletes five rows from that table, the trigger fires five times, once for each row.

What is the difference between row level trigger and table level trigger?

Triggers can be broadly classified into Row Level and Statement Level triggers….Difference between Row level and Statement level triggers.

Row Level Triggers Statement Level Triggers
“FOR EACH ROW” clause is present in CREATE TRIGGER command. “FOR EACH ROW” clause is omitted in CREATE TRIGGER command.

What is a triggering statement in Oracle?

A triggering statement or a statement within a trigger can cause one or more integrity constraints to be checked. Also, triggers can contain statements that cause other triggers to fire (cascading triggers). Oracle uses the following execution model to maintain the proper firing sequence of multiple triggers and constraint checking:

What happens if you omit schema from trigger in Oracle?

If you omit schema, then Oracle Database creates the trigger in your own schema. trigger Specify the name of the trigger to be created. If a trigger produces compilation errors, then it is still created, but it fails on execution.

Can the trigger target a single schema or the whole database?

The trigger can target a single schema or the whole database. Granular information about triggering events can be retrieved using event attribute functions. Valid events are listed below. For a full description click the link.

How are triggers created and disabled in Oracle 11g?

Prior to Oracle 11g, triggers are always created in the enabled state. In Oracle 11g, triggers can now be created in the disabled state, shown here. Specific triggers are disabled and enabled using the ALTER TRIGGER command.