Attach Enhancement in Image/SQL

by Maheedhar PV — Commercial Systems Division

Introduction

Currently, when a database is attached to Allbase DBE through the IMAGESQL utility, all the datasets including automatic masters are attached. Similarly, at the time of attaching all the compound items are split into simple items. This enhancement to IMAGESQL utility is to add two new options for the ATTACH command. The options are:

Not to attach automatic masters (NOAUTO)
Not to split the compound items (NOAUTOSPLIT).

Why this Enhancement?

NOAUTO

Currently, when an attach command is issued all the data sets in the database are written into the ATCINFO file, and are registered with Allbase DBE. This enhancement allows you to have an option of not registering automatic masters during attach, as data retrieval is never done from automatic masters. If the NOAUTO option is used, the views involving the automatic masters are also not created and the data from the automatic masters cannot be viewed.

NOAUTOSPLIT

Currently, during the attach time, all the Image data types are mapped to their nearest equivalent in the SQL data types. If the equivalent data type does not exist, they are mapped to char data type of the equivalent size. The compound items in the Image database are automatically split as individual items. By splitting of the compound items the number of items of a dataset can exceed 1023 (the limit in a table in Allbase). This enhancement provides an option for not to split the compound items, but register them as a single item even if the count of no of items in the dataset is below the limit. The compound items are treated as single item and are mapped to their nearest SQL data type which if not available are mapped to char.

Changes in User Interface

The syntax of the Attach command is

ATTACH     [WITH OWNER=owner]     [NOAUTO or NA]     [NOAUTOSPLIT or NAS]
                                  [AUTO]             [AUTOSPLIT]

        Examples           ATTACH           ATTACH NOAUTO           ATTACH AUTOSPLIT           ATTACH WITH OWNER = DOCUMENT           ATTACH WITH OWNER = DOCUMENT NOAUTO NOAUTOSPLIT

The default behavior of the ATTACH command is retained as is today, i.e. the automatic masters are attached, and compound items split.

Conclusion

This enhancement:

Does not change the default behavior of the ATTACH command of IMAGESQL utility
Allows a new option NOAUTO in the ATTACH command not to attach the automatic masters
Allows a new option NOAUTOSPLIT in the ATTACH command not to split the compound items.