LANSA Table Concepts

A table is a database table in which records can be retrieved, added, changed or deleted. In IBM i terminology, a table may be a physical table or an index.

To create a table, LANSA uses a Repository-based Table Definition. This table definition is a database independent definition of the table characteristics.

A table definition contains:

• The real fields (columns) in the table that make up the format of the table records. Some keys may be nominated as keys to the table.

• 1.6.3 Index Development of the table that are required. The indexes may contain select/omit criteria.

In addition the LANSA table definition may also contain:

• 1.6.4 Virtual Column Development that are columns which are not actually present in the database table but are derived from fields that are in it. Hence the name virtual. These columns appear as if they were in the table, even though they are not.

• 1.6.5 Table Rules & Triggers Development that are to be performed on columns when records are added, updated or deleted.

• 1.6.6 Access Route Development from the current table to other tables in the system. This facility allows users to access a complete database without having a detailed knowledge of its structure.

• 1.6.7 Predetermined Join Column Development which use the current table's access routes to retrieve information from related tables.

• 1.6.8 Batch Control Development  which specifies other tables in the system that contain batch, control or summary totals of information in the current table. LANSA will ensure that the summary or control information in other tables is automatically maintained.

Some points to note about working with table definitions are:

• The table definition name and actual physical table name are always the same. When LANSA requests that the name of a table definition be supplied, specify the name of the physical table (as opposed to the name of any associated indexes/ tables).

• The allowed field types in a table are determined by the partition settings. For more details, refer to  RDML and RDMLX Partition Concepts in the Administrator Guide.

• Within the LANSA System, indexes are considered to be part of the table definition.

• The table definition contains the attributes of the associated physical table and all associated indexes.