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Question Database




11) How many types of table buffering are there?


• Buffering types:

– Single record: Only records actually being processed are moved into the buffer. This type of buffering preserves buffer space but requires more database hits in order to load the table. Recommended for large tables when only a few records need to be accessed.



– Generic: A subset of the table records is loaded based on part of the primary key. Recommended if only certain “generic” areas of the table will be needed.


– Full: Results in either all of the table or none of it being loaded into the buffer. Recommended for a) tables up to 30 K in size, b) larger tables where access is needed to many records, and c) tables against which attempts to access data will frequently yield a “no record found” result.



12) What is an index? What is the use of an index?

An index serves as a sorted copy of the table reduced to specific fields, with a pointer to the remaining fields.

Indexes accelerate the reading of tables when the system looks for records satisfying specific search criteria.

The system determines the most efficient index by which to select data for the specific request.



13) What is Database Utility?


• The Database (DB) Utility is a tool used in SAP to serve as a interface between the database management software (i.e., ORACLE, INFORMIX, DB2, INGRES, etc.) and the ABAP Dictionary.


It is used to:


– Convert data (i.e., change field lengths and data types, etc.)

– Activate objects in the ABAP Dictionary

– Create tables and indices

– Perform all standard table operations in the database that were entered in the ABAP Dictionary

• The DB Utility automatically writes the SQL commands necessary to create, change and delete tables and indexes in the physical database, and records the tables in the ABAP Dictionary.


• As the DB Utility is operating, a log file gets created which contains information on whether or not the conversion was successful and the point of failure during the conversion if it was not successful.


• The DB Utility can be run either online or in the background.


• You can also manually run the DB Utility from any ABAP Dictionary screen under the UTILITIES menu or transaction SE14.


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