|
91) What is the difference between primary key & unique index ?
Primary : a relational database constraint. Primary key consists of one or
more columns that uniquely identify a row in the table. For a normalized
relation, there is one designated primary key.
Unique index: a physical object that stores only unique values. There can be
one or more unique indexes on a table.
92) What is sqlcode -922 ?
Authorization failure
93) What is sqlcode -811?
SELECT statement has resulted in retrieval of more than one row.
94) What does the sqlcode of -818 pertain to? –
This is generated when the consistency tokens in the DBRM and the load module
are different.
95) Are views updateable ?
Not all of them. Some views are updateable e.g. single table view with all
the fields or mandatory fields. Examples of non-updateable views are views which
are joins, views that contain aggregate functions(such as MIN), and views that
have GROUP BY clause.
|
