Most frequently Asked DB2 Interview Questions and Answers for freshers and experienced pdf free download
1) What is DB2 (IBM Database 2)?
DB2 is a subsystem of the MVS operating system. It is a Database Management System (DBMS) for that operating system.
2) What is an access path?
The path that is used to get to data specified in SQL statements.
3) What is an alias?
It is an alternate name that can be used in SQL statements to refer to a table or view in the same or remote DB2 subsystem.
4) Explain what a plan is?
Plan is a DB2 object (produced during the bind process) that associates one or more database request modules with a plan name.
5) What is a DB2 bind?
Bind is a process that builds “access paths” to DB2 tables. A bind uses the Database Request Modules(s) (DBRM(s)) from the DB2 pre-compile step as input and produces an application plan.
It also checks the user’s authority and validates the SQL statements in the DBRM(s).
6) What information is used as input to the bind process?
The database request module produced during the pre-compile. The SYSIBM.SYSSTMT table of the DB2 catalog.
7) What is meant by the attachment facility?
The attachment facility is an interface between DB2 and TSO, IMS/VS, CICS, or batch address spaces. It allows application programs to access DB2.
8) What is meant by AUTO COMMIT?
AUTO COMMIT is a SPUFI option that commits the effects of SQL statements automatically if they are successfully executed.
9) What is a base table?
A base table is a real table - a table that physically exists in that there are physical stored records.
10) What is the function of buffer manager?
The buffer manager is the DB2 component responsible for physically transferring data between an external medium and (virtual) storage (performs the actual I/O operations). It minimizes the amount of physical I/O actually performed with sophisticated buffering techniques(i.e., read-ahead buffering and look-aside buffering).
11) What is a buffer pool?
A buffer pool is main storage that is reserved to satisfy the buffering requirements for one or more tablespaces or indexes, and is made up of either 4K or 32K pages.
12) How many buffer pools are there in DB2?
There are four buffer pools: BP0, BP1, BP2, and BP32.
13) On the create tablespace, what does the CLOSE parameter do?
CLOSE physically closes the tablespace when no one is working on the object. DB2 (release 2.3) will logically close tablespaces.
14) What is a clustering index?
It is a type of index that (1) locates table rows and (2) determines how rows are grouped together in the tablespace.
15) What will the COMMIT accomplish?
COMMIT will allow data changes to be permanent. This then permits the data to be accessed by other units of work. When a COMMIT occurs, locks are freed so other applications can reference the just committed data.
16) What is meant by concurrency?
Concurrency is what allows more than one DB2 application process to access the same data at essentially the same time. Problems may occur, such as lost updates, access to uncommitted data, and un-repeatable reads.
17) What is cursor stability?
It is cursor stability that “tells” DB2 that database values read by this application are protected only while they are being used. (Changed values are protected until this application reaches the commit point). As soon as a program moves from one row to another, other programs may read or the first row.
18) What is the function of the Data Manager?
The Data Manager is a DB2 component that manager the physical databases. It invokes other system components, as necessary, to perform detailed functions such as locking, logging, and physical I/O operations (such as search, retrieval, update, and index maintenance).
19) What is a Database Request Module(DBRM)?
A DBRM is a DB2 component created by the DB2 pre-compiler containing the SQL source statements extracted from the application program. DBRMs are input to the bind process.
20) What is a data page?
A data page is a unit of retrievable data, either 4K or 32K (depending on how the table is defined), containing user or catalog information.
1) What is DB2 (IBM Database 2)?
DB2 is a subsystem of the MVS operating system. It is a Database Management System (DBMS) for that operating system.
2) What is an access path?
The path that is used to get to data specified in SQL statements.
3) What is an alias?
It is an alternate name that can be used in SQL statements to refer to a table or view in the same or remote DB2 subsystem.
4) Explain what a plan is?
Plan is a DB2 object (produced during the bind process) that associates one or more database request modules with a plan name.
5) What is a DB2 bind?
Bind is a process that builds “access paths” to DB2 tables. A bind uses the Database Request Modules(s) (DBRM(s)) from the DB2 pre-compile step as input and produces an application plan.
It also checks the user’s authority and validates the SQL statements in the DBRM(s).
6) What information is used as input to the bind process?
The database request module produced during the pre-compile. The SYSIBM.SYSSTMT table of the DB2 catalog.
7) What is meant by the attachment facility?
The attachment facility is an interface between DB2 and TSO, IMS/VS, CICS, or batch address spaces. It allows application programs to access DB2.
8) What is meant by AUTO COMMIT?
AUTO COMMIT is a SPUFI option that commits the effects of SQL statements automatically if they are successfully executed.
9) What is a base table?
A base table is a real table - a table that physically exists in that there are physical stored records.
10) What is the function of buffer manager?
The buffer manager is the DB2 component responsible for physically transferring data between an external medium and (virtual) storage (performs the actual I/O operations). It minimizes the amount of physical I/O actually performed with sophisticated buffering techniques(i.e., read-ahead buffering and look-aside buffering).
11) What is a buffer pool?
A buffer pool is main storage that is reserved to satisfy the buffering requirements for one or more tablespaces or indexes, and is made up of either 4K or 32K pages.
12) How many buffer pools are there in DB2?
There are four buffer pools: BP0, BP1, BP2, and BP32.
13) On the create tablespace, what does the CLOSE parameter do?
CLOSE physically closes the tablespace when no one is working on the object. DB2 (release 2.3) will logically close tablespaces.
14) What is a clustering index?
It is a type of index that (1) locates table rows and (2) determines how rows are grouped together in the tablespace.
15) What will the COMMIT accomplish?
COMMIT will allow data changes to be permanent. This then permits the data to be accessed by other units of work. When a COMMIT occurs, locks are freed so other applications can reference the just committed data.
16) What is meant by concurrency?
Concurrency is what allows more than one DB2 application process to access the same data at essentially the same time. Problems may occur, such as lost updates, access to uncommitted data, and un-repeatable reads.
17) What is cursor stability?
It is cursor stability that “tells” DB2 that database values read by this application are protected only while they are being used. (Changed values are protected until this application reaches the commit point). As soon as a program moves from one row to another, other programs may read or the first row.
18) What is the function of the Data Manager?
The Data Manager is a DB2 component that manager the physical databases. It invokes other system components, as necessary, to perform detailed functions such as locking, logging, and physical I/O operations (such as search, retrieval, update, and index maintenance).
19) What is a Database Request Module(DBRM)?
A DBRM is a DB2 component created by the DB2 pre-compiler containing the SQL source statements extracted from the application program. DBRMs are input to the bind process.
20) What is a data page?
A data page is a unit of retrievable data, either 4K or 32K (depending on how the table is defined), containing user or catalog information.
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