1  DEFINE_FIELD
   Creates a global field definition.

   When the DEFINE FIELD statement executes, Oracle Rdb adds the field
   definition to the physical database. A field definition includes
   a name, a data type, and a set of optional clauses.

   Example:


   DEFINE FIELD LABEL
      DATATYPE IS TEXT SIZE IS 8 CHARACTERS
      MISSING_VALUE IS "Not here"
      VALID IF LABEL =  "Good"       OR
               LABEL =  "Bad"        OR
               LABEL =  "Mediocre"   OR
               LABEL MISSING
      QUERY_HEADER FOR DATATRIEVE IS "Column"/"Label".
 

2  More
   To define a field using the DEFINE FIELD statement, you must have
   the Oracle Rdb DEFINE privilege for the database.

   If you have invoked the database with the PATHNAME specification,
   the field definition is also added to the data dictionary. Once
   you have defined a field globally, any relation can use the
   field definition by using the field name in the DEFINE or CHANGE
   RELATION statement.

   You can copy a shareable field definition from the data
   dictionary into the database.

   You must execute this statement in a read/write transaction.
   If there is no active transaction and you issue this statement,
   Oracle Rdb starts a read/write transaction implicitly.

   Other users are allowed to be attached to the database when you
   issue the DEFINE FIELD statement.
 

2  Format

 (B)0DEFINE FIELD qqqqqqqqq> name qqqqqqqqqqqqqqqqqqqq>qqqqqqqqqqqqqqqqqqqqk
                                                                       x
 lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
 x
 mqwqqqq> FROM PATHNAME qqqqqqqqqqqqqqq> path-name qqqqqq>qqqqqqqwqqqq> .
   x                                                             x
   mqwqqqqqqqqqqqqqqq>qqqqqqqqqqqqqqqwqqq> field-attributes qqqqqj
     mq> DESCRIPTION IS /* text */ qqj

 

3  name
   Name of the field you want to create. You must use a field name
   that conforms to OpenVMS naming conventions.
 

3  path-name
   A full or relative data dictionary path name specifying the
   source of the field definition. You must invoke the database by
   path name if you plan to copy a shareable field definition from
   the data dictionary.

   The name you give to the field must match the name of the field
   in the data dictionary. You cannot rename a shareable field.
 

3  text
   A text string that adds a comment to the field definition.
 

3  field-attributes
   A list of definitions that indicate what type of data you can
   store in the field and how Oracle Rdb uses that data. The field
   attributes include the data type and the following optional
   clauses:

   o  VALID IF

   o  MISSING_VALUE

   o  DATATRIEVE support clauses

Do not use multiple, conflicting clauses in a field definition.

   For a complete description of field attributes, ask for HELP on
   Field_attr.
 

2  Examples
   Example 1: Using DEFINE FIELD

   DEFINE FIELD STANDARD_ID_NUMBER
       DATATYPE IS SIGNED LONGWORD.

   This statement gives a name to the field and specifies its data
   type.

   Example 2: Using DEFINE FIELD with VALID IF

   DEFINE FIELD SEX
      DATATYPE IS TEXT SIZE IS 1
      VALID IF SEX = "M" OR SEX = "F".

   This definition provides validation criteria. When a user tries
   to enter a value other than "M" or "F" in a field that refers to
   this definition, Oracle Rdb returns an error message.

   Example 3: Using DEFINE FIELD with DATATRIEVE Support

   DEFINE FIELD SALARY_AMOUNT
       DATATYPE IS SIGNED LONGWORD
       DEFAULT_VALUE FOR DATATRIEVE IS 0
       EDIT_STRING FOR DATATRIEVE IS "$$$$,$$9.99".

   This example adds a DATATRIEVE edit string and default value to
   the name and data type.

   Example 4: Copying a Field from the data dictionary

   DEFINE FIELD SALARY_AMOUNT
     FROM PATHNAME 'DISK1:[CDDPLUS.DEFS]PERS.SALARY_AMOUNT'.

   This example copies the shareable field, SALARY_AMOUNT, from the
   dictionary.