Use the CREATE DISTINCT TYPE statement to create a new distinct data
type.
Only Dynamic Server supports this statement, which is an extension
to the ANSI/ISO standard for SQL.
A distinct type is a data type based on a built-in
data type or on an existing opaque data type, a named ROW data type, or another
distinct data type. Distinct data types are strongly typed. Although the distinct
type has the same physical representation of data as its source type, values
of the two types cannot be compared without an explicit cast from one type
to the other.
To create a distinct
data type, you must have the Resource privilege on the database. Any user
with the Resource privilege can create a distinct type from one of the built-in
data types, which user informix owns.
Important:
You cannot create
a distinct type on the
SERIAL or
SERIAL8 data types.
To create a distinct type from an opaque type, from a named ROW type, or
from another distinct type, you must be the owner of the data type or have
the Usage privilege on the data type.
By default, after a distinct type is defined, only the owner of the distinct
type and the DBA can use it. The owner of the distinct type, however, can
grant to other users the Usage privilege on the distinct type.
A distinct type has the same storage structure as its source type. The
following statement creates the distinct type birthday,
based on the built-in DATE data type:
CREATE DISTINCT TYPE birthday AS DATE
Although Dynamic Server uses the same storage format for the distinct type as it
does for its source type, a distinct type and its source type cannot be compared
in an operation unless one type is explicitly cast to the other type.
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>>-CREATE DISTINCT TYPE--distinct_type--AS--source_type--------><