Question: What Cannot Be Done On A View?

Can we create view from view?

Creating Views Views can be created from a single table, multiple tables or another view.

To create a view, a user must have the appropriate system privilege according to the specific implementation.

CREATE VIEW view_name AS SELECT column1, column2……

What are the different types of triggers?

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 a trigger written for a view *?

Yes, you can create triggers on views. (Since at least SQL Server 2000.) If you create a trigger on a view, it won’t fire on inserts to the base table. If you want something to happen when you insert data into a base table, create a trigger on the base table.

Are views updatable?

The SQL UPDATE VIEW command can be used to modify the data of a view. All views are not updatable. So, UPDATE command is not applicable to all views. An updatable view is one which allows performing a UPDATE command on itself without affecting any other table.

What can be done on a view?

A view can hide the complexity that exists in a multiple table join. Views allows the user to select information from multiple tables without requiring the users to actually know how to perform a join. Views can be used to store complex queries.

What command is used to delete a view?

DROP VIEW commandA view is deleted with the DROP VIEW command.

What Cannot have a trigger associated with it?

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.More items…

What are the after triggers?

After Trigger, Instead of Trigger ExampleAfter Trigger (using FOR/AFTER CLAUSE) This trigger fires after SQL Server completes the execution of the action successfully that fired it. … Instead of Trigger (using INSTEAD OF CLAUSE) This trigger fires before SQL Server starts the execution of the action that fired it.

Can one trigger initiate another trigger?

Both DML and DDL triggers are nested when a trigger performs an action that initiates another trigger. These actions can initiate other triggers, and so on. DML and DDL triggers can be nested up to 32 levels.

What triggered?

Triggers are anything that remind someone of previous trauma. To be triggered is to have an intense emotional or physical reaction, such as a panic attack, after encountering a trigger.

What is SQL trigger 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.

Which view does not always allow DML operations through the view?

DML operations could not always be performed through a complex view. INSERT, DELETE and UPDATE are directly possible on a simple view. We cannot apply INSERT, DELETE and UPDATE on complex view directly.

Can we insert and delete rows into a view?

You can insert, update, and delete rows in a view, subject to the following limitations: If the view contains joins between multiple tables, you can only insert and update one table in the view, and you can’t delete rows. You can’t directly modify data in views based on union queries.

What are SQL triggers?

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. … SQL Server lets you create multiple triggers for any specific statement.

Can we perform DML on view?

A view can be defined as a virtual table or a stored query and the data accessible through a view is not stored in the database as a distinct object. … However, views can be used and perform DML operations ( Insert , Update & Delete ) also.