How many types of views are there in SQL Server?

What are SQL Server views?

A VIEW in SQL Server is like a virtual table that contains data from one or multiple tables. It does not hold any data and does not exist physically in the database. … It contains a set of predefined SQL queries to fetch data from the database. It can contain database tables from single or multiple databases as well.

Where are views stored?

View is a simple SQL statement that is stored in database schema (INFORMATION_SCHEMA. Views). So when ever we call the view the SQL statement gets executed and return the rows from main physical table. You can also tell the view as a Logical table that store the defination (the sql statement) but not the result.

Should I use views SQL?

Not only are views… Views are virtual tables that can be a great way to optimize your database experience. Not only are views good for defining a table without using extra storage, but they also accelerate data analysis and can provide your data extra security.

What is the difference between views and tables?

A view consists of rows and columns just like a table. The difference between a view and a table is that views are definitions built on top of other tables (or views), and do not hold data themselves. If data is changing in the underlying table, the same change is reflected in the view.

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Can we use DML in view?

Short answer: Yes. But there are restrictions. Any modifications, including UPDATE, INSERT, and DELETE statements, must reference columns from only one base table. The columns that are being modified in the view must reference the underlying data in the table columns directly.

What are triggers in SQL?

A SQL trigger is a database object which fires when an event occurs in a database. We can execute a SQL query that will “do something” in a database when a change occurs on a database table such as a record is inserted or updated or deleted. For example, a trigger can be set on a record insert in a database table.

What are three types of views?

Point of view is the perspective from which a story is told. There are 3 types of point of views: 1st person point of view, 2nd person point of view, and 3rd person point of view.

Why do we use views?

Views are used for security purposes because they provide encapsulation of the name of the table. Data is in the virtual table, not stored permanently. Views display only selected data. We can also use Sql Join s in the Select statement in deriving the data for the view.

What is view explain?

transitive verb. 1 : to look at attentively : scrutinize, observe view an exhibit. 2a : see, watch. b : to look on in a particular light : regard doesn’t view himself as a rebel. 3 : to survey or examine mentally : consider view all sides of a question.

What is the difference between view and materialized view?

Views are generally used when data is to be accessed infrequently and data in table get updated on frequent basis. On other hand Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.

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How do you write a trigger?

create trigger [trigger_name]: Creates or replaces an existing trigger with the trigger_name. [before | after]: This specifies when the trigger will be executed. {insert | update | delete}: This specifies the DML operation. on [table_name]: This specifies the name of the table associated with the trigger.

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