User's Manual

Metadata for the IMS/DB Data Source
Advanced Tuning of the Metadata A-3
Columns Tab
Use the Columns tab to specify metadata that describe the table columns. The tab is
divided into the following:
■ Column Definition Section
■ Column Properties
The Columns tab is shown in the following figure:
Organization Select how the record represented by the table is
organized. The options that are displayed depend on the
record. The following options are available:
■ Index
■ Sequential
■ Relative: Used with RRDS files. Access to a specific
record number of a relative file is performed by using
a pseudo column to specify the record position. The
hash symbol (#) is used to specify a pseudo column.
For example:
SELECT * FROM colleges WHERE # = 6
Record format Specifies how the record, represented by the table, is
formatted. The options that are displayed depend on the
record. The IMS/DB records have a fixed format.
Maximum record
length
The maximum allowable size of a record (in bytes).
DB Command IMS/DB specific commands are displayed in the DB
Command section of the General tab. The information
displayed is generated automatically when the metadata is
generated and should not be modified.
Filter Expression A WHERE clause. This clause is added to every query
accessed using this metadata. The filter is specified
without the WHERE keyword. Specify a filter when more
than one logical table is stored in the same physical file.
Table A–1 (Cont.) General Tab Components
Field Description