Draw the diagram of logical structure of oracle database and explain it in brief.

Q.n. 2 Draw the diagram of logical structure of oracle database and explain it in brief.

The Oracle database is divided into increasingly smaller logical units to manage, store, and retrieve data efficiently and quickly. The figure shows the relationships between the logical structures of the database.

Logical structure mainly consists of table space, segments, extents, and oracle data blocks

TABLE SPACE 

 Each database is logically divided into one or more table spaces . One or more data files are explicitly created for each table space to physically store the data of all logical structures in a tables pace. The combined size of the data files in a table space is the total storage capacity of the table space.

SEGMENT 

 A segment is a set of extents allocated for a certain logical structure. The segments can be of one of following type data segment, index segment, temporary segment, rollback segment.

EXTENT 

The next level of logical database space is an extent. An extent is a specific number of contiguous data blocks, obtained in a single allocation, and used to store a specific type of information.

ORACLE DATA BLOCKS

 At the finest level of granularity, Oracle database data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk. The standard block size is specified by the DB_BLOCK_SIZE initialization parameter. In addition, you can specify up to five other block sizes.