7 17 DEF_ARRAY

LANSA Technical

7.17 DEF_ARRAY

The DEF_ARRAY command is used to define an array structure within an RDML function.

The array created by this command can be used for:

1. Grouping up to 1000 individual identical fields into contiguous storage, thus allowing "indexed" references to be made to any one of the fields. To do this, use the OF_FIELDS parameter. This is the only option supported for RDMLX fields. Note that if an object is not enabled for RDMLX it is limited to 100 fields.

2. Overlaying a large field with an array structure, thus allowing "indexed" references to individual areas within the larger field. To do this, use the OVERLAYING parameter. This option is not supported when using an RDMLX field.

This command provides full array support to LANSA applications.

However, it must be emphasized that the use of array constructs in database files is NOT considered to be the best long term strategy in terms of relational database design.

This facility is provided as a concession to reality. Array structures within files provide better system performance than fully normalized relational database designs.

However, the presence of this facility should not be construed in any way as encouraging the use of array structures in database designs.

Whenever hardware resources permit, a fully relational design will always yield a simpler, easier to use, easier to maintain and longer lasting solution.

Also See

7.17.1 DEF_ARRAY Parameters

7.17.2 DEF_ARRAY Comments / Warnings

7.17.3 DEF_ARRAY Examples

Required

DEF_ARRAY ---- NAME --------- #name of array ----------------->

>-- INDEXES ------ #index field name -------------->

| |

----- 50 max -------

>-- OF_FIELDS ---- #field name -------------------->

| expandable group expression |

---------- 100 max --------------