1  –  CONSTANT

    Syntax options:

    CONSTANT | UPDATABLE

    CONSTANT changes the variable into a declared constant that
    cannot be updated. If you specify CONSTANT, you must also have
    specified the DEFAULT clause to ensure the variable has a value.
    CONSTANT also indicates that the variable cannot be used as
    the target of an assignment or be passed as an expression to a
    procedure's INOUT or OUT parameter.

    UPDATABLE is the default and allows the variable to be modified.
    An update of a variable can occur due to a SET assignment, an
    INTO assignment (as part of an INSERT ... RETURNING, UPDATE ...
    RETURNING, or SELECT statement), or as a procedure's OUT or INOUT
    parameter on a CALL statement.

2  –  data-type

    Specifies the data type assigned to the variable. See the Data_
    Types HELP topic for more information on data types.

3  –  default-clause

    You can only use references to simple literal values and other
    declared variables as a default.

4  –  domain-name

    Specifies the domain name assigned to the variable. The domain
    supplies the data type and, for interactive SQL, the edit string
    of the variable.

    See the User_Supplied_Names HELP topic for more information on
    domain names.

5  –  variable-name

    Specifies the local variable.