7 Nested table A column in table may be made up of a user defined table as in

7 nested table a column in table may be made up of a

This preview shows page 3 - 4 out of 4 pages.

7)Nested table:A column in table may be made up of a user -defined table as in thecase of items within an order. In such cases, the inner table, which is known as a nested table, is stored as a separate segment.8)Bootstrap Segment:A bootstrap segment, also known as a cache segment is created by the sql. bsq script When a database is created. This segment helps to initialize the data dictionary cache when the database is opened by an instance.The bootstrap segment cannot be queried or updated and does notrequire any maintenance by the database administrator.9)Oracle data blocks containBlock header: The header contains the data block address, table directory, row directory, and transaction slots that are usedwhen transactions make changes to rows in the block. Block headers grow from the top down.Data space: Row data is inserted into the block from the bottom up.Free space:The free space in a block is in the middle of theblock thus both the header and the row data space can growwhen necessary. The free space in a block is contiguousinitially. However, deletions and updates may fragment the freespace in the block. The free space in the block is coalesced bythe Oracle server when necessary.
Background image
Image of page 4

You've reached the end of your free preview.

Want to read all 4 pages?

  • Spring '16
  • Oracle Database, Oracle Corporation, Disk partitioning

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture