Mainframe DB2 Interview Questions and Answers Part-2
The physical database is managed by the DB2 component called Data manager. It invokes other system components to perform logging, locking etc.
12.) What is a storage group (STOGROUP)?
STOGROUP is a named collection of DASD volumes, which is to be used by index spaces and table spaces of the database.
13.) Define predicate?
Predicate is an element of a search condition. It expresses or implies a search condition.
14.) Define Declaration Generator (DCLGEN).
Declaration Generator is a facility that is used to form SQL statements that describes a table or view. At pre-compile time, the table or view descriptions are then used to check the validity of SQL statements.
15.) List out the buffer pools in DB2
There are four buffer pools in DB2 and they are:
16.) Define clustering index.
Clustering index is a type of index, which locates the table rows and determines how to group the rows together in the tablespace.
17.) What is concurrency?
More than one DB2 application process can access the same data at the same time, is known as concurrency. However, problems can happen such as, lost updates access to unrepeatable reads and uncommitted data.
18.) Explain the Function done by data manager?
Data manager can be considered as a component that is capable of managing the databases that are physically present and is capable of invoking other components associated with the system for performing functionalities like logging, locking and in performing other I/O operations.
19.) Explain about DBRM.
DBRM stands for Database Request Module and is a component inside DB2, which is created by the pre compiler of DB2. This is a module that consists of SQL source statements that get extracted out of the application program. DBRMs form inputs that are helpful in the binding process.
20.) Define Data page.
Data page can be considered as a unit that is capable of retrieving data from the database. The database from which the data can be retrieved is in the form of 4 kilobytes or 32 kilobytes. The form in which data is retrieved depends on the way the table is defined inside the database. Data page also contains information regarding the catalog or user that are part of the database.