16.10 - PREV - Teradata Database

Purpose

The PREV command displays a previous row, WAL log record, DB, WDB, DBD, WDBD, CI, WCI, CID, WCID or subtable.

Syntax

/dispopt

Can be one of the following values:

• /S displays a short formatted display of the object. This is the default.
• /M displays a medium-length formatted display of the object.
• /L displays a long formatted display of the object.
• /H displays a hexadecimal display of the object.
• /X displays an extended display of the object.
• /Z displays for compressed values:
  • 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.

/rowopt

Can be one of the following values:

• /P positions to the physical rows or table requested. At least one physical row must be in the selected range. Nothing is displayed unless there is a problem. Physical rows store one of several types of data, such as regular table row data or column partition data.
• /C or /S counts the number of physical rows selected. This is the default for all subtables except the table header subtable.
• /I or /M displays only the row header information (length, RowID, and flags).
• /L or /R display the formatted row header and the fields in the physical row. This option is the default for the table header subtable. However, this option will not be the default formatted field display because the table header subtable is a special row format and requires special formatting.
• /H displays the entire physical row in hexadecimal, including the row header.

number

The number of objects to display, starting with the first object following the end of the current context.

The default is 1.

Usage Notes

If number is specified, PREV displays previous objects of the same type until the requested number is reached. PREV sets the context to the objects displayed.

If a whereclause is saved in the context, PREV will apply the conditions of the whereclause. For more information about the whereclause, see DISPLAY and Specifying a WHERE Clause.

PREV displays the objects previous to the beginning of the current context as shown in the following table.