DB2 Questions and Answers
1. What is DB2 ( IBM Database 2 )?
|DB2 is subsystem of the MVS operating system. It is a Database Management System ( DBMS ) for that operating system.|
2. What are a precompiler?
|It is a DB2 facility for static SQL statements - it replace these statements with calls to the DB2 language interface module.|
3. List out the buffer pools in DB2
|There are four buffer pools in DB2 and they are: BP0 BP1 BP2 BP32|
4. Mention the downsides of PAGE level lock.
|In case if there are large updates to be done, then the resource utilization is high accordingly.|
5. 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.|
6. What is an access path?
|The path that is used to get to data specified in SQL statements.|
7. What is the purpose of using COMMIT?
|The data changes can be made permanent by using COMMIT. It also permits data to be accessed by other applications who can reference the committed data|
8. What are the various locking levels available?
|PAGE, TABLE, TABLESPACE|
9. How and when does the Db2 enforces the unique key?
|DB2 utilizes unique index to avoid identical key values storage in database - A unique index must be created whenever a table is to be created with primary key - DB2 marks the table as unavailable until the needed indexes are created explicitly - DB2 prevents the duplicate entities into the table that has unique key - A unique key is declared by using the UNIQUE clause of CREATE TABLE command - DB2 enforces the unique index when INSERT,UPDATE statements are applied to the table. - DB2 also enforces the unique index during the LOAD utility execution|
10. What is a DB2 bind?
|A DB2 bind is a process that builds an access path to DB2 tables A BIND process establishes a relationship between an APPLICATION PROGRAM and its RELATIONAL DATA.|