Data Level Descriptor

A data level descriptor is a D-pointerClosed An item in a dictionary with D/CODE D that points directly at a lower level data structure. The lower level structure can be another dictionary or it can be a data section.  which defines a data section and any associated index sections. It is held in a file dictionary and is similar to a file definition item in an MD.

Attribute Description
Item-id Data section name.
  001

D {I} {L||R} {C} {T} {X|Y}

where:

D Marks a Definition Item.

I Specifies that the file contains case-insensitive item-ids.

L Specifies that the file is to be logged by Transaction Logging. This is the default setting when a file is created.

R Specifies that the file is not logged by Transaction Logging, but that its data will be recovered during the automatic recovery of a database configured for Rapid Recovery.

C Specifies that the dictionary or file contains or has contained compiled DataBasic programs. Added when you compile a program.

T Specifies that the file does not take part in transactions. As a result, if a transaction is aborted, the changes will not be rolled back. It is recommended that this code is used for application log files.

X Specifies that the data section will not be saved by the SAVE command.

Y Specifies that the SAVE command will not save the data in the data section. An empty data section is saved and can be restored.

Notes

  • For more information on the logging status of files, refer to the description of the TL-SET-LOG-STATUS command.
  • The X and Y codes also affect FILE-SAVE and ACCOUNT-SAVE which use the SAVE command. Use of the O option in the SAVE command overrides the X and Y codes.
  002

The first value defines the location of the data section, as follows:

start, modulo, id{,scatter{,firstSplit}}

where:

startis the logical block number of the start of data section.

modulois the modulo or, for an AFS file, the initial modulo of the data section.

idis the reuse identifier.

scatteris the number of blocks in the scatter map (scattered and AFS files).

firstSplitis the first group to be split after file creation (AFS files).

The second and subsequent values contain the same information for any indexes associated with the file.
  003

The first value is the same as for a File Definition Item, except as follows:

  • The second character is '3' (data section).
  • For a normal file on the local database the first character is 'B'.
  • For a directory view on the local database the first character is 'D'. The third character onwards contain the path of the host directory.
  • For a special file on the local database the first character is 'E'. The third character onwards contain the type of special file and any additional parameters.

The second and subsequent values contain the initial modulos of any indexes associated with the file.
  004 The first value contains File trigger information. The second and subsequent values contain the names of any indexes associated with the data section.
  005 Optional. Retrieval lock code(s).
  006 Optional. Update lock code(s).
  007 Optional. Conversion codes for English to display item-ids.
  008 Optional V (sublist) code for English.
  009

Mandatory. Contains a code specifying the type of alignment to be used by English. Must be one of the following:

LLeft aligned.

RRight aligned.

TText aligned. Text wraps at word boundaries.

UUnlimited.

Note: For more details, refer to the topic Data Definition Item.
  010 Maximum width of item-id column. Defaults to 10 when the data level descriptor is created.
  011 Not used and reserved.
  012 Null.
  013 The first value contains reallocation parameters for the data section. The second and subsequent values contain reallocation parameters for any indexes associated with the data section.

Single Level Dictionary Files

If a dictionary has no data sections associated with it (that is, it is a single level file), it contains no data level descriptors. It does, however, have a Q-pointer that points back to itself. Refer to the topic File Synonym Definition Item. A single level dictionary file can be useful if you wish to create a global dictionary to reference with the USING clause in an English statement.