1 – char-data-types
A character type. See the Data_Types HELP topic for more
information on data types.
2 – character-set-name
A valid character set.
3 – COLLATING_SEQUENCE
Specifies a collating sequence for the named domain.
The OpenVMS National Character Set (NCS) utility provides a
set of predefined collating sequences and also lets you define
collating sequences of your own. The COLLATING SEQUENCE clause
accepts both predefined and user-defined NCS collating sequences.
Before you use the COLLATING SEQUENCE clause in a CREATE DOMAIN
statement, you must first specify the NCS collating sequence for
SQL using the CREATE COLLATING SEQUENCE statement. The sequence-
name argument in the COLLATING SEQUENCE clause must be the same
as the sequence-name in the CREATE COLLATING SEQUENCE statement.
4 – COMMENT_IS
Adds a comment about the domain. SQL displays the text of the
comment when it executes a SHOW DOMAIN statement. Enclose the
comment in single quotation marks ( ') and separate multiple
lines in a comment with a slash mark (/).
5 – DATABASE ALIAS alias
In the FROM path-name clause, specifies the name for an attach
to a particular database. SQL adds the domain definition to the
database referred to by the alias.
If you do not specify an alias, SQL adds the domain definition to
the default database. See the User_Supplied_Names HELP topic for
more information on default databases and aliases.
6 – date-time-data-types
A data type that specifies a date, time, or interval. See the
Data_Types HELP topic for more information about date-time data
types.
7 – DEFAULT value-expr
Provides a default value for a domain.
You can use any value expression including subqueries,
conditional, character, date/time, and numeric expressions as
default values. See Value Expressions for more information about
value expressions.
For more information about NULL, see the NULL_Keyword HELP topic.
The value expressions described in Value Expressions include
DBKEY and aggregate functions. However, the DEFAULT clause is
not a valid location for referencing a DBKEY or an aggregate
function. If you attempt to reference either, you receive a
compile-time error.
If you do not specify a DEFAULT for a column, it inherits the
DEFAULT from the domain. If you do not specify a default for
either the column or domain, SQL assigns NULL as the default
value.
8 – domain-constraint
Creates a constraint for the named domain.
Specify a domain constraint when you create a domain to limit
which values can be stored in columns based on the domain. Domain
constraints specify that columns based on the domain contain only
certain data values or that data values can or cannot be null.
Use the CHECK clause to specify that a value must be within a
specified range or that it matches a list of values. When you
specify a CHECK clause for a domain constraint, you ensure that
all values stored in columns based on the domain are checked
consistently.
9 – domain-name
The name of a domain you want to create. The domain name must be
unique among domain names in the schema. You can qualify it with
an alias or (in multischema databases only) a schema name.
10 – FROM pathname
Specifies the repository path name of a repository field
definition. SQL creates the domain using the definition from
this field and gives the domain the name of the field definition.
Creating a domain based on a repository domain definition is
useful when many applications share the same definition. Changes
to the common definition can be automatically reflected in all
applications that use it.
You can create a domain using the FROM path-name clause only if
the field definition in the repository was originally created
using the repository CDO utility. For instance, you cannot create
a domain using the FROM path-name clause if the definition was
created in the repository as part of an SQL session. Oracle
Rdb requires that the field names referenced in the VALID IF
expression of the CDO utility match the name of the global field
being defined or changed.
NOTE
Changes by other users or applications to the field
definition in the repository will affect the domain
definition once the database is integrated to match the
repository with an INTEGRATE DATABASE . . . ALTER FILES
statement.
You can use the FROM path-name clause only if the database was
attached specifying PATHNAME. You can specify either a full
repository path name or a relative repository path name.
You cannot specify formatting clauses when you use the FROM path-
name form of the CREATE DOMAIN statement.
You cannot use the FROM path-name clause when embedding a CREATE
DOMAIN statement in a CREATE DATABASE statement.
11 – data-type
Syntax options:
IS data-type
AS data-type
A valid SQL data type. See the Data_Types HELP topic for more
information on data types.
12 – NO_COLLATING_SEQUENCE
Specifies that this domain uses the standard default collating
sequence, that is, ASCII. Use the NO COLLATING SEQUENCE clause to
override the collating sequence defined for the database in the
CREATE DATABASE or ALTER DATABASE statement.
13 – sql-and-dtr-clause
Optional SQL and DATATRIEVE formatting clause. See the DATATRIEVE
HELP topic for more information on formatting clauses.
14 – STORED_NAME_IS
Specifies a name that Oracle Rdb uses to access a domain created
in a multischema database. The stored name lets you access
multischema definitions using interfaces, such as Oracle RMU,
the Oracle Rdb management utility, that do not recognize multiple
schemas in one database. You cannot specify a stored name for a
domain in a database that does not allow multiple schemas. For
more information about stored names, see the User_Supplied_Names
HELP topic.