SQLite Views

A View is nothing more than an SQLite statement stored in the database with an associated name. A View is actually a combination of tables in the form of a predefined SQLite query.

A View can contain all rows of a table or selected rows from one or more tables. A View can be created from one or more tables, depending on the SQLite query used to create the view.

A View is a virtual table that allows users to accomplish the following:

  • Users or user groups can find structured data in a more natural or intuitive way.

  • Restrict data access, so users can only see limited data rather than the complete table.

  • Summarize data from various tables to generate reports.

SQLite views are read-only, so you may not be able to execute DELETE, INSERT, or UPDATE statements on a view. However, you can create a trigger on a view, which fires when an attempt is made to DELETE, INSERT, or UPDATE the view, and the actions to be taken are defined in the trigger body.

Create View

SQLite views are created usingCREATE VIEWstatement. SQLite views can be created from a single table, multiple tables, or other views.

The basic syntax of CREATE VIEW is as follows:

CREATE [TEMP | TEMPORARY] VIEW view_name AS
SELECT column1, column2.....
FROM table_name
WHERE [condition];

You can include multiple tables in the SELECT statement, in a manner very similar to a normal SQL SELECT query. If the optional TEMP or TEMPORARY keyword is used, the view will be created in a temporary database.

Examples

Suppose the COMPANY table has the following records:

ID          NAME        AGE         ADDRESS     SALARY
----------  ----------  ----------  ----------  ----------
1           Paul        32          California  20000.0
2           Allen       25          Texas       15000.0
3           Teddy       23          Norway      20000.0
4           Mark        25          Rich-Mond   65000.0
5           David       27          Texas       85000.0
6           Kim         22          South-Hall  45000.0
7           James       24          Houston     10000.0

Now, here is an example of creating a view from the COMPANY table. The view only selects a few columns from the COMPANY table:

sqlite> CREATE VIEW COMPANY_VIEW AS
SELECT ID, NAME, AGE
FROM  COMPANY;

Now, you can query COMPANY_VIEW in a similar way to querying an actual table. Below is an example:

sqlite> SELECT * FROM COMPANY_VIEW;

This will produce the following result:

ID          NAME        AGE
----------  ----------  ----------
1           Paul        32
2           Allen       25
3           Teddy       23
4           Mark        25
5           David       27
6           Kim         22
7           James       24

Drop View

To drop a view, simply use theview_nameDROP VIEW statement. The basic syntax of DROP VIEW is as follows:

sqlite> DROP VIEW view_name;

The following command will drop the COMPANY_VIEW view that we created earlier:

sqlite> DROP VIEW COMPANY_VIEW;
Other Extensions