What is the meaning of data blocks ?

[bhakti2]

hi,

What is the exact meaning of "data blocks" in the following paragraph ?

Index records and table records are organized in data blocks.

If you dispatch an SQL statement from an ABAP program to the database, the program searches for the data records requested either in the database table itself (full table scan) or by using an index (index unique scan or index range scan). If all fields requested are found in the index using an index scan, the table records do not need to be accessed.

A data block shows the level of detail in which data is written to the hard disk or read from the hard disk. Data blocks may contain multiple data records, but a single data record may be spread across several data blocks.

thanks

bhakti

[deepak_dhamat]

Hi ,

As Per oracle , data is stored in database in form of Data blocks , extent and Segments .

Physical space of memory is allocated to store data .

first level is called BLOCKS ,nexxt is extent and last is SEGMENT .

each block can store multiple data records and Conversly large no of data records can be stored in data Blocks .

data is stored in DATA BLOCKS which is smallest unit in oracle where data is stored in bytes .

regards

Deepak.

[yuri_ziryukin]

To make it simple:

- data block is the smallest unit, which is operated on during reading data from disk and placing it to the data cache.

If I remember correctly, in Oracle the default block size for SAP is 8 Kb.

[bhakti2]

thanks for useful explaination