Communicator e3000 MPE/iX Release 7.5 (Software Release C.75.00) (30216-90336)

Chapter 5
Technical Articles
Attach Enhancement in Image/SQL
128
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.