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NOTE: If you want to uniquely identify an entry in your file by a
combination of fields, and to force that uniqueness, then you will most likely
want to create a KEY on your file, rather than using Identifier fields (which
don't force the uniqueness).If a field is part of the PRIMARY KEY for a file,
then it should not be marked as an Identifier as well.
See the "Key Definition" topic for details.
An identifier is a designation you can give to a field that you want permanently associated with the .01 field (NAME) of a file. The SSN field of our PATIENT file example has been defined as an identifier field. Each time a patient's entry is referenced, the SSN will be displayed to help positively identify the entry. When a new entry is added to the file, the user will be asked to provide the SSN.
A field that is not multiple-valued can be specified as an identifier for a file simply by using the Identifier option in the Utility Functions.
A multiple-valued field cannot be designated as an identifier, however, a subfield of that multiple-valued field can be designated as an identifier for the multiple. The DIAGNOSIS field in the PATIENT file cannot, for example, be designated as an identifier, but its subfield AGE AT ONSET can be designated as an identifier of DIAGNOSIS. This feature is discussed in more detail later in this section.
These are the steps for setting up the sample SSN field as an identifier:
MODIFY WHAT FILE: PATIENT Select FIELD: SSN Want to make 'SSN' an identifier? NO// Y (YES) Want to display SSN whenever a lookup is done on an entry in the 'PATIENT' file? YES // (YES)
Here, the positive answer to the last question causes the patient's SSN value to show up whenever a lookup on a patient is done. For example:
Select PATIENT NAME: DOE 1 DOE,JANE 323223333 2 DOE,JANET 414114444 CHOOSE 1-2:
An identifier field will not be asked if its WRITE access security does not match the VA FileMan access code of the user. If the identifier field has been specified (in the Modify File Attributes option) as a required field, the user must type a valid answer to its prompt when it is asked as an identifier; otherwise, the entry just created is deleted.
Using the up-arrow key ("^") for jumping is not allowed for identifier fields in the Enter or Edit File Entries option when adding a new entry. If you attempt to use the up-arrow key in a field designated as an identifier in an edit session, the entry just created is deleted. Since the SSN field in our example is mandatory and an identifier, this ensures that every patient in our PATIENT file will have an SSN recorded.
As mentioned above, you could make the AGE AT ONSET subfield an identifier for the multiple DIAGNOSIS field as follows:
Select UTILITY OPTION: IDENTIFIER Select FIELD: DIAGNOSIS (multiple) Select DIAGNOSIS SUB-FIELD: AGE AT ONSET Want to make 'AGE AT ONSET' an Identifier? NO// Y (YES) Want to display AGE AT ONSET whenever a lookup is done on an entry in the 'DIAGNOSIS' file? YES// N (NO)
As a result of this dialogue, every time a new DIAGNOSIS for a patient is entered, the AGE AT ONSET would be asked. The AGE AT ONSET would not, however, be automatically displayed at subsequent DIAGNOSIS lookups.
To drop a field's status as an identifier, simply return to the Identifier option, select the field, and answer YES to the question:
Field is already an Identifier; want to delete it? NO// Y
Reviewed/Updated: March 4, 2007