DBSHORT - Interpretation of Database Field Short Names

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# DBSHORT - Interpretation of Database Field Short Names

This Natural profile and session parameter can be used to determine the interpretation of database field short names. It corresponds to the option `DBSHORT` of the Natural system command `COMPOPT`.

A database field defined in a DDM is described by two names:

- the short name with a length of 2 characters, used by Natural to communicate with the database (especially with Adabas);

- the long name with a length of 3-32 characters (1-32 characters, if the underlying database type accessed is Db2/SQL), which is supposed to be used to reference the field in the Natural programming code.

Under special conditions, you may reference a database field in a Natural program with its short name instead of the long name. This applies if running in Reporting Mode without Natural Security and if the database access statement contains a reference to a DDM instead of a view.

The decision if a field name is regarded as a short-name reference depends on the name length. When the field identifier consists of two characters, a short-name reference is assumed; a field name with another length is considered as a long-name reference. This standard interpretation rule for database fields can additionally be influenced and controlled by setting the compiler option `DBSHORT` to `ON` or `OFF`:

Possible settings | `ON` | Using a short name is allowed for referencing a database field. However, a data base short name is not permitted in general (even if `DBSHORT=ON`) for the definition of a field when a view is created; when a `DEFINE DATA LOCAL` statement was specified; when running under Natural Security.
`OFF` | A database field may only be referenced via its long name. Every database field identifier is considered as a long-name reference, regardless of its length. If a two character name is supplied which can only be found as a short name but not as a long name, syntax error NAT0981 is raised at compile time. This makes it possible to use long names defined in a DDM with 2-byte identifier length. This option is essential if the underlying database you access with this DDM is SQL (Db2) and table columns with a two character name exist. For all other database types (for example, Adabas), however, any attempt to define a long field with a 2-byte name length will be rejected at DDM generation. Moreover, if no short-name references are used (what can be enforced via `DBSHORT=OFF`), the program becomes independent of being compiled without Natural Security.
Default setting | `ON` |
Dynamic specification | yes
Specification within session | yes
Applicable statements | `OPTIONS`
Applicable command | Either `GLOBALS` or `DBSHORT` option of `COMPOPT`

#### Examples:

Assume the following data base field definition in the DDM `EMPLOYEES`:

Short Name | Long Name
--- | ---
`AA` | `PERSONNEL-ID`

Example 1:

    OPTIONS DBSHORT=ON
    READ EMPLOYEES
      DISPLAY AA      /* data base short name AA is allowed
    END

Example 2:

    OPTIONS DBSHORT=OFF
    READ EMPLOYEES
      DISPLAY AA      /* syntax error NAT0981, because DBSHORT=OFF
    END

Example 3:

    OPTIONS DBSHORT=ON
    DEFINE DATA LOCAL
    1 V1 VIEW OF EMPLOYEES
      2  PERSONNEL-ID
    END-DEFINE
    READ V1 BY PERSONNEL-ID
      DISPLAY AA     /* syntax error NAT0981, because PERSONNEL-ID is defined in view;
                     /* (even if DBSHORT=ON)
    END-READ
    END