The Firebird 5.0 Language Reference | ALTER DOMAIN

`ALTER DOMAIN` Examples

Changing the data type to INTEGER and setting or changing the default value to 2,000:
```
ALTER DOMAIN CUSTNO
  TYPE INTEGER
  SET DEFAULT 2000;
```
Renaming a domain.
```
ALTER DOMAIN D_BOOLEAN TO D_BOOL;
```

Deleting the default value and adding a constraint for the domain:

ALTER DOMAIN D_DATE
  DROP DEFAULT
  ADD CONSTRAINT CHECK (VALUE >= date '01.01.2000');

Changing the CHECK constraint:

ALTER DOMAIN D_DATE
  DROP CONSTRAINT;

ALTER DOMAIN D_DATE
  ADD CONSTRAINT CHECK
    (VALUE BETWEEN date '01.01.1900' AND date '31.12.2100');

Changing the data type to increase the permitted number of characters:
```
ALTER DOMAIN FIRSTNAME
  TYPE VARCHAR(50) CHARACTER SET UTF8;
```
Adding a NOT NULL constraint:
```
ALTER DOMAIN FIRSTNAME
  SET NOT NULL;
```
Removing a NOT NULL constraint:
```
ALTER DOMAIN FIRSTNAME
  DROP NOT NULL;
```

`DROP DOMAIN`

Drops an existing domain

Available in

DSQL, ESQL

Syntax

DROP DOMAIN domain_name

The DROP DOMAIN statement deletes a domain that exists in the database.It is not possible to delete a domain if it is referenced by any database table columns or used in any PSQL module.To delete a domain that is in use, all columns in all tables that refer to the domain have to be dropped and all references to the domain have to be removed from PSQL modules.

Who Can Drop a Domain

The DROP DOMAIN statement can be executed by:

Administrators
The owner of the domain
Users with the DROP ANY DOMAIN privilege

Example of `DROP DOMAIN`

Deleting the COUNTRYNAME domain

DROP DOMAIN COUNTRYNAME;

ALTER DOMAIN Examples

ALTER DOMAIN Examples

DROP DOMAIN

Who Can Drop a Domain

Example of DROP DOMAIN

`ALTER DOMAIN` Examples

`DROP DOMAIN`

Example of `DROP DOMAIN`