FAQs(106 to 120)

106) How many buffer pools are there in DB2?

A) There are four buffer pools: BP0, BP1, BP2, and BP32.

107) On the create tablespace, what does the CLOSE parameter do?

A) CLOSE physically closes the tablespace when no one is working on the object. DB2 (release 2.3) will logically close tablespaces.

108) What is a clustering index?

A) It is a type of index that (1) locates table rows and (2) determines how rows are grouped together in the tablespace.

109) What will the COMMIT accomplish?

A) 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.

110) What is meant by concurrency?

A) 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.

111) What is cursor stability?

A) 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.

112) What is the function of the Data Manager?

A) 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).

113) What is a Database Request Module(DBRM)?

A) 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.

114) What is a data page?

A) 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.

115) What are data types?

A) They are attributes of columns, literals, and host variables. The data types are SMALLINT, INTEGER, FLOAT, DECIMAL, CHAR, VARCHAR, DATE and TIME.

116) What is Declaration Generator(DCLGEN)?

A) DCLGEN is a facility that is used to generate SQL statements that describe a table or view. These table or view descriptions are then used to check the validity of other SQL statements at precompile time. The table or view declares are used by the DB2I utility DCLGEN to build a host language structure, which is used by the DB2 precompiler to verify that correct column names and data types have been specified in the SQL statement.

117) What does DSNDB07 database do?

A) DSNDB07 is where DB2 does its sorting. It includes DB2?s sort work area and external storage.

118) What will the FREE command do to a plan?

A) It will drop(delete) that existing plan.

119) What is a host variable?

A) This is a data item that is used in an SQL statement to receive a value or to supply a value. It must be preceded by a colon (:) to tell DB2 that the variable is not a column name.

120) What is a buffer pool?

A) 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.