Quick Answer: Can A Trigger Be Created On A View?

What is difference between before and after triggers?

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..

What are the after triggers?

After Trigger in SQL Server These kinds of triggers fire after the execution of an action query that can be either DDL statements like Create, Alter and Drop or DML statements like Insert, Update and Delete.

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.

Can we call trigger manually?

no, you can’t call a trigger on sql server manually, if u want to execute trigger you have to genrate the event with which trigger is associated. … No we can’t execute trigger manually. It is fired automatically.

Is mutating trigger function may not see it?

The Oracle mutating trigger error occurs when a trigger references the table that owns the trigger, resulting in the “ORA-04091: table name is mutating, trigger/function may not see it.” message. Don’t use triggers – The best way to avoid the mutating table error is not to use triggers.

What is an example of a trigger?

The definition of a trigger is the mechanism on a gun that makes it shoot a bullet or anything that starts a series of events. An example of trigger is what a cop presses to fire his gun. An example of trigger is a hostile confrontation that causes a series of bad memories with the person.

What is instead of trigger?

What is an INSTEAD OF trigger. An INSTEAD OF trigger is a trigger that allows you to skip an INSERT , DELETE , or UPDATE statement to a table or a view and execute other statements defined in the trigger instead. … In other words, an INSTEAD OF trigger skips a DML statement and execute other statements.

What are the different types of trigger?

Types of TriggersData Manipulation Language (DML) Triggers. DML triggers are executed when a DML operation like INSERT, UPDATE OR DELETE is fired on a Table or View. … Data Definition Language (DDL) Triggers. … LOGON Triggers. … CLR Triggers.

Can we create trigger on view in Oracle?

If the view has an INSTEAD OF trigger, it will automatically skip the DML statement and execute other DML statements instead. … In Oracle, you can create an INSTEAD OF trigger for a view only. You cannot create an INSTEAD OF trigger for a table.

Can we create after trigger on view in SQL Server?

SQL Server Triggers on Views There are two kinds of DML triggers the FOR (or AFTER) trigger and the INSTEAD OF trigger, but the only one you can use with views are INSTEAD OF triggers.

How do you write a trigger?

Creating TriggersCREATE [OR REPLACE] TRIGGER trigger_name − Creates or replaces an existing trigger with the trigger_name.{BEFORE | AFTER | INSTEAD OF} − This specifies when the trigger will be executed. … {INSERT [OR] | UPDATE [OR] | DELETE} − This specifies the DML operation.More items…

How can you tell if a trigger is fired in SQL Server?

To test if a trigger fires you can add a PRINT statement to the trigger (e.g. “PRINT ‘trigger fired!’ “), then do something that should trigger the trigger. If you get the printed text in your messages-tab in management studio you know it fired.

Why use triggers in Salesforce?

Typically, you use triggers to perform operations based on specific conditions, to modify related records or restrict certain operations from happening. You can use triggers to do anything you can do in Apex, including executing SOQL and DML or calling custom Apex methods.

What is trigger old?

Trigger.New and Trigger.Old are both the context Variables which returns records in List’s. Trigger.New => works for the NEW values that are entering either it may be Insert or Update. Trigger.Old=> works for the OLD values that are already in the Fields, it may be to Delete or Update the records.

Which statement can a trigger not be based on?

Since triggers execute as part of a transaction, the following statements are not allowed in a trigger: All create commands, including create database, create table, create index, create procedure, create default, create rule, create trigger, and create view. All drop commands. alter table and alter database.