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1.4 What SQL terminology should I know?
Key points
An SQL table is similar to a TurboIMAGE data set.
An SQL row has one or more columns.
You can create hash indexes, B-tree indexes or parent-child relationships
(referential constraints) on SQL tables.
In SQL, security is primarily based on the end-user's logon id, not on a
password. The DBA grants and revokes database priviledges to a particular
logon id. The DBA can also define a group, and grant/revoke to the group
in the same way as to a particular logon id. Each logon id added to the
group has the same priviledges as the group. Finally, the DBA can add groups
to other groups.
In TurboIMAGE, several types of transactions are defined. A dynamic
transaction is a logical transaction which has the following attributes:
- It begins with a DBXBEGIN call and normally ends with a DBXEND call; it can
be rolled back dynamically with a DBXUNDO call.
- It spans only one database. A program can open more than one database if it
needs to access data sets from different databases, and can have dynamic
transactions in effect on different databases at the same time.
In DBCORE, only one type of transaction is defined. A DBCORE transaction is
essentially equivalant to a TurboIMAGE dynamic transaction, and has the
following attributes:
Page last updated on November 29, 1995
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