Quick Answer: What Is Compound Trigger?

What is trigger explain with example?

Trigger: A trigger is a stored procedure in database which automatically invokes whenever a special event in the database occurs.

For example, a trigger can be invoked when a row is inserted into a specified table or when certain table columns are being updated..

What are the types of trigger?

Types of Triggers in OracleDML Trigger: It fires when the DML event is specified (INSERT/UPDATE/DELETE)DDL Trigger: It fires when the DDL event is specified (CREATE/ALTER)DATABASE Trigger: It fires when the database event is specified (LOGON/LOGOFF/STARTUP/SHUTDOWN)

Can we write trigger on view?

Triggers may be created on views, as well as ordinary tables, by specifying INSTEAD OF in the CREATE TRIGGER statement. If one or more ON INSERT, ON DELETE or ON UPDATE triggers are defined on a view, then it is not an error to execute an INSERT, DELETE or UPDATE statement on the view, respectively.

Can we call trigger inside stored procedure?

You cant call Trigger from Stored Procedure, as Trigger are created on table and get fired implicitly. But you can call stored procedure to from trigger, but do remeber it should not be recursive.

Why trigger is used in SQL?

A trigger is a special type of stored procedure that automatically runs when an event occurs in the database server. DML triggers run when a user tries to modify data through a data manipulation language (DML) event. DML events are INSERT, UPDATE, or DELETE statements on a table or view.

How do you commit inside a trigger?

Yes, you can commit inside the trigger. But for this you have to make this trigger transaction to be an Independent transaction from its parent transaction, you can do this by using Pragma. Pragma AUTONOMOUS_TRANSACTION allow you to build the Independent (child) Transaction, started by another.

Can we write exception in trigger?

1 Answer. You’re almost there; you need a DECLARE block in a trigger if you want to declare anything; this means that your WHEN clause is in the wrong place. A few points: Never catch an exception and then call DBMS_OUTPUT.

Can rollback or commit issued inside a trigger code?

Changes made within triggers should thus be committed or rolled back as part of the transaction in which they execute. For this reason, triggers are NOT allowed to execute COMMIT or ROLLBACK statements (with the exception of autonomous triggers).

What are examples of emotional triggers?

Below is an introduction to 7 important psychological and emotional triggers that can increase your sales, backed up with examples and further reading.Belonging. … Fear. … Guilt. … Trust. … Leadership. … Values. … (Instant) Gratification.

What is a trigger pulse?

[′trig·ər ‚pəls] (electronics) A pulse that starts a cycle of operation. Also known as tripping pulse.

What is the difference between a row level trigger and a statement level trigger?

Row-level triggers execute once for each row in a transaction. … Statement-level triggers execute once for each transaction. For example, if a single transaction inserted 500 rows into the Customer table, then a statement-level trigger on that table would only be executed once.

What are after triggers?

Before triggers: used to update or validate record values before they’re saved to the database. After triggers: used to access field values that are set by the system (such as a record’s Id or LastModifiedDate field) and to effect changes in other records. The records that fire the after the trigger is read-only.

What are the components of a compound trigger?

What are the components of a compound trigger? Declaration section and all four timing sections. Declaration section and at least two timing sections. Declaration section, referencing section, and timing sections.

What is trigger and its types?

Triggers are stored programs, which are automatically executed or fired when some events occur. Triggers are, in fact, written to be executed in response to any of the following events − A database manipulation (DML) statement (DELETE, INSERT, or UPDATE) A database definition (DDL) statement (CREATE, ALTER, or DROP).

How do you run a trigger?

Running a TriggerIn the Databases folder in Enterprise Explorer, under the database connection profile, expand the navigation tree for the appropriate database and schema owner. … Expand the Tables folder, the table where the trigger is located, and then the Triggers folder.Right-click the trigger and select Run.More items…

What triggered?

Triggers are anything that might cause a person to recall a traumatic experience they’ve had. For example, graphic images of violence might be a trigger for some people. Less obvious things, including songs, odors, or even colors, can also be triggers, depending on someone’s experience.

What is the difference between after and before trigger?

Before triggers execute before the data has been committed into the database. … After triggers execute after the data has been inserted or updated in the database. Usually after triggers are used because you need access to a formula field or the Id in the case of an insert.

How triggers can be declared *?

Triggers can be defined as row triggers or statement triggers. Statement triggers are fired once for each triggering statement regardless of the number of rows in a table affected by the triggering statement. For example if a DELETE statement deletes several rows from a table, a statement trigger is only fired once.

What is statement level trigger?

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 mutating in the trigger?

A mutating table error (ORA-04091) occurs when a row-level trigger tries to examine or change a table that is already undergoing change (via an INSERT, UPDATE, or DELETE statement). In particular, this error occurs when a row-level trigger attempts to read or write the table from which the trigger was fired.

Is commit needed after insert?

So yes, by default, if you’re just using INSERT , the records you insert will be committed, and there is no point trying to roll them back. (This is effectively the same as wrapping each statement between BEGIN and COMMIT .)