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Definition of view

  • In SQL, a view is a virtual table based on the result-set of an SQL statement.
  • A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database.
 sql view
  • In database theory, a View is the result set of a stored query on the data, which the database users can query just as they would in a persistent database collection object.
  • This pre-established query command is kept in the database dictionary.
  • As a result set, it is a virtual table computed or collated dynamically from data in the database when access to that view is requested.
  • A view is a virtual table and it 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.

The Syntax to create a sql view is:

CREATE VIEW view_name AS
SELECT column1, column2, ...
FROM table_name
WHERE condition;
  • view_name is the name of the VIEW.
  • The SELECT statement is used to define the columns and rows that you want to display in the view.
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For Example: to create a view on the product table the sql query would be like

CREATE VIEW [Current Product List] AS
SELECT ProductID, ProductName
FROM Products
WHERE Discontinued = No;

Views offer the following advantages:

  • Ease of use: A view hides the complexity of the database tables from end users. Essentially we can think of views as a layer of abstraction on top of the database tables.
  • Space savings: Views takes very little space to store, since they do not store actual data.
  • Additional data security: Views can include only certain columns in the table so that only the non-sensitive columns are included and exposed to the end user. In addition, some databases allow views to have different security settings, thus hiding sensitive data from prying eyes.

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