Used in : Postgre sql
CREATE DOMAIN creates a new domain. A domain is essentially a data type with optional constraints (restrictions on the allowed set of values). The user who defines a domain becomes its owner.
Domains are useful for abstracting common constraints on fields into a single location for maintenance. For example, several tables might contain email address columns, all requiring the same CHECK constraint to verify the address syntax. Define a domain rather than setting up each table’s constraint individually.
CREATE DOMAIN CPI_DATA AS REAL CHECK (value >= 0 AND value <= 10);
Now CPI_DATA domain is create so, we can use this domain anywhere in any table of database as below :
CREATE TABLE student( sid char(9) PRIMARY KEY, name varchar(30), cpi CPI_DATA );
Every time cpi_data will check the constraint, when you add data in student table.
Example 1 :
Insert into student values (201501408,Raj,7.5); This will not violate the property of cpi.
Example 2 :
Insert into student values (201501188,Dhaval,12); ERROR. This will violate the property of cpi.
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- SQL | CREATE
- SQL | Create Table Extension
- SQL | SELECT Query
- SQL | Distinct Clause
- SQL | WHERE Clause
- SQL | AND and OR operators
- SQL | INSERT INTO Statement
- SQL | DELETE Statement
- SQL | UPDATE Statement
- SQL | SELECT TOP Clause
- SQL | ORDER BY
- SQL | Aliases
- SQL | Wildcard operators
- SQL | Join (Inner, Left, Right and Full Joins)
- SQL | Union Clause
- SQL | Join (Cartesian Join & Self Join)
- SQL | DROP, TRUNCATE
- SQL | GROUP BY
- SQL | SOME
- SQL | LIKE
Improved By : Umesh Bhat