15.00 - DB - Teradata Database

Teradata Database Support Utilities

prodname
Teradata Database
vrm_release
15.00
category
Configuration
featnum
B035-1180-015K

DB

Purpose  

The DB (Data Block) command selects and displays the DB segment that starts at the specified cylinder and sector number.

Syntax  

Note: The online help lists the display options (/P, /S, /M, /L, /H, /X, /V) as /dispopt. You can type the options at the beginning or end of the command.

 

Syntax Element

Description

/P

Positions to the DB. If one does not exist, an error occurs. Nothing is displayed unless a problem exists.

/S

A formatted display of the block, header, block trailer, and first and last row header.

/M

A formatted display of the block, header, block trailer, first and last row header, and the intervening row headers.

/L

A formatted display of the block, header, block trailer, first and last row header, the intervening row headers, and the row content in hex following each row header.

/H

A formatted display of the DB header followed by the entire DB in hex.

/X

Same as /L.

/V

Verifies that the DB is logically correct but does not display it.

/C

For compressed data blocks, displays the uncompressed DB header information, including extended header information pertaining to data compression.

If the scoped DB is not compressed, the output is similar to the display when the /S option is used.

/Z

For compressed data blocks, displays:

  • the uncompressed DB header information, including extended header information pertaining to data compression.
  • a hex format display of the compressed data stored in the DB. If the /Z option is not used, the hex display shows the uncompressed data.
  • If the scoped DB is not compressed, the output is similar to the output when the
    /x option is used.

    FORCE

    Formats as DB even if the block code indicates otherwise. Without FORCE, the command fails on a mismatched block.

    cylid

    The 64-bit identifier of a cylinder, entered as a 16‑character hexadecimal number.

    sectorcount

    The sector count.

    =

    Filer will use the most recently saved values for cylid, sectornum, or sectorcount.

    This option cannot be used unless input values have already been defined for cylid, sectornum, or sectorcount. For more information, see “Stored Input Values” on page 82.

    Usage Notes  

    Since the DB command only displays parameters from the data block itself, this command does not display any checksum field values for the DB. Checksum field values for the DB are stored in the DBD in the CI. To display the checksum fields for a DB, either the DBD should be displayed using the DBD command or use the CHECKSUM command.

    A DB contains one or more rows, all of which are members of the same subtable. Any single row is contained fully within a single DB. In addition, every DB must be fully contained within a cylinder.

    If count is omitted, Filer reads in the first sector of the block and obtains the sector count from the DB header. If given, Filer attempts to display only the information contained in those sectors.

    If the segment accessed is not a DB, Filer displays a message indicating an assumed type, unless you specify FORCE, in which case Filer tries to format the block as a DB. The prompt for the DB selector is shown below:

    DB ==>

    In addition to global and upper-level commands, the following lower-level commands are allowed at the DB prompt:

  • ACCESS
  • DBROW
  • DISPLAY
  • DELETE
  • NEXT
  • PACK
  • PATCH
  • PREV
  • RENAME
  • TRASH
  • WRITE
  • The BLK command is similar to DB, except it can display other types of segments in addition to Data Blocks. For more information, see “BLK” on page 109.