DB2



1. What is DB2 ?  

DB2 is a Database Management System for the MVS Operating System where, DB2 is a subsystem of MVS Operating System.



2. 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



3. How many type of Data types available in DB2 ?  

The Data types available here are:
1. SMALLINT
 
2. INTEGER
 
3. FLOAT
 
4. DECIMAL
 
5. CHAR
 
6. VARCHAR
 
7. DATE
 
8. TIME



4. What is CHECK constraint ?  

It is specified as a condition or criteria to ensure data integrity. A value to be inserted or updated to a table is tested by CHECK constraint. The CHECK constraints are created during the creation of the table.




5. What is DB2 bind ?  

The process that builds access paths to the DB2 table is known as bind. The bind uses Database Request Modules from the DB2 pre-compile step as input and produces an application plan. It checks for user authentication and validates SQL statements in the DBRM(s).



6. What is buffer pool?  

The buffer pool is a reserved main storage, which is to satisfy the buffering requirements for one or more table spaces or indexes. It can be made up of either 4K or 32K pages.



7. Explain the function of Data Manager.  

The physical database is managed by the DB2 component called Data manager. It invokes other system components to perform logging, locking etc.



8. 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.



9. Define predicate?  

Predicate is an element of a search condition. It expresses or implies a search condition.



10. 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.



11. List out the buffer pools in DB2  

There are four buffer pools in DB2 and they are:
  • BP0
  • BP1
  • BP2
  • BP32


12. 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.



13. 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.



14. 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.



15. 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.



16. 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.



17. Explain about RCT ?  

RCT is expanded as Resource – Control Table and is defined in the DB2/CICS region. This is the component that comprises of features that are gathered through macros of DSNCRCT. RCT matches with the transaction ID that of CICS, with the authorization ID that of DB2. This should also be matched with plan ID.



18. How can tablespace be moved to another DASD volume that is allocated for that tablespace?  

Tablespace that you are using is allocated only to STOGROUP, then you can enter the command ALTER STOGROUP for adding as well as deleting volume. REORG TABLESPACE and RECOVER TABLESPACE are statements that are helpful in creating new STOGROUP that can point towards the new volume. ALTER tablespace and REORG and RECOVER are statements used for altering and recovering the tablespace allocated in the memory.



19. Which utility is used to load data into a table from a sequential file?  

Load utility is used to load data into tables.



20. Which utility reclaims space from pages when some rows were deleted?  

Reorg utility is used for reorganization of data on physical storage.



Java Interview Question

.Net Interview Question

PHP Interview Question

AngularJS Interview Questions