DEFINE FIELDGROUP command
Summary
Status
Available as of Model 204 release 7.5
Privileges
Any user
Function
To establish the contents of a field group, including the fields and field groups associated with the field group being defined.
Syntax
DEFINE FIELDGROUP FieldGroupName [WITH FIELDGROUP OuterGroupName]
Where:
- FieldGroupName specifies the name of the field group you are defining.
- OuterGroupName specifies the name of another field group previously defined. The field group being defined is nested under the OuterGroupName.
Example
To define a field group MAKE_MODEL with fields MAKE and MODEL in it, you would write the following definition.
DEFINE FIELDGROUP MAKE_MODEL DEFINE FIELD MAKE WITH FIELDGROUP MAKE_MODEL AND ORDERED - CHARACTER DEFINE FIELD MODEL WITH FIELDGROUP MAKE_MODEL
Example of a field group within a field group:
DEFINE FIELDGROUP BIRDS WITH FIELDGROUP VERTEBRATES
Usage
Defining fields after defining the containing field group makes it possible to later add fields to an already defined field group, for example:
DEFINE FIELD YEAR WITH FIELDGROUP MAKE_MODEL
The keyword AND on field definitions means that a field group name can contain blanks, just like a field name. You must use the AND keyword to separate the field group name from subsequent attributes:
DEFINE FIELD COLOR WITH FIELDGROUP MAKE_MODEL AND ORDERED - CHARACTER
The AND is unnecessary, if the FIELDGROUP FieldGroupName clause is the last field attribute:
DEFINE FIELD COLOR WITH ORDERED CHARACTER FIELDGROUP - MAKE_MODEL
Note The MAKE_MODEL field group must be defined before defining the field(s) and/or field group(s) that belong with it.
The default attribute for frequency of occurrence for fields in a field group is EXACTLY-ONE, whereas the default for individually defined fields is REPEATABLE. Of course, you can declare a field inside a field group as REPEATABLE, as well as AT-MOST-ONE.
Usage notes
The fields defined in a field group definition follow the syntax rules described in the DEFINE FIELD command.
The WITH FIELDGROUP clause identifies a field group that is already defined.
Field group names must be unique among themselves and cannot have the same name as any field.
Once you define a field you cannot move it into or out of a fieldgroup using a REDEFINE command. You must delete the field and relocate it by defining it again, locating it where you want it.
Nested field groups
Nested field groups are limited to 16 levels. The syntax for nesting is designed as follows:
DEFINE FIELDGROUP VERTEBRATES DEFINE FIELDGROUP BIRDS WITH FIELDGROUP VERTEBRATES DEFINE FIELDGROUP PARROTS WITH FIELDGROUP BIRDS DEFINE FIELDGROUP OWLS WITH FIELDGROUP BIRDS DEFINE FIELDGROUP REPTILES WITH FIELDGROUP VERTEBRATES DEFINE FIELDGROUP SNAKES WITH FIELDGROUP REPTILES
Attribute considerations
A field in a field group cannot have the OCCURS or INVISIBLE attribute. You can assign any other attributes you choose, paying attention to those that conflict with each other.
The REPEATABLE and AT-MOST-ONE field attribute have different behavior for fields inside a field group. The REPEATABLE attribute means that the field can have more than one occurrence inside a field group occurrence, whereas the AT-MOST-ONE attribute means that the field can have only a single occurrence inside a field group occurrence. The AT-MOST-ONE attribute is the default for fields inside a field group.