DBD, PSB, and ACB maps
DBD/PSB/ACB Mapper generates DBD, PSB, and ACB maps in the SYSPRINT data set.
- A DBD map for each DBD.
- A PSB map for each database PCB within the PSB.
- An ACB (PSB) map for each database PCB within the PSB-type ACB.
- An ACB (DBD) map for each DBD-type ACB.
Format of the maps
The maps produced by DBD/PSB/ACB Mapper depict the hierarchical structure of a database as described in a DBD. The map heading shows the DBD member name, volume serial number, and data set name of the library that contains the member. The creation date, time, and IMS version of the DBD are shown on the right of the data set name. It also shows the access method, or if it is a logical database LOGICAL, for the DBD currently being mapped. Both physical and logical relationships are shown. A map can be created for all full-function and Fast Path IMS database organizations except GSAM. A map cannot be created for a GSAM database, because it does not contain segments. However, a report can be created.
For physical relationships, each segment is represented by a box that contains the segment name and code. Each box (except for the root segment) is connected to its physical parent and siblings. The characters as shown in the following table are used to draw a box that shows the data set group that contains the segment. These characters are called data set group characters.
Character | Explanation |
---|---|
* | The first data set group |
+ | The second data set group |
" | The third data set group |
. | The fourth data set group |
= | The fifth data set group |
- | The sixth data set group |
# | The seventh data set group |
% | The eighth data set group |
; | The ninth data set group |
' | The 10th data set group |
V | Virtual logical child |
C | Pointer and parent segment concatenation |
Data set group characters are used to express up to the maximum number of data set groups allowed for a database. A DEDB database can have up to 9999 areas. The area segments use the same characters as the data set groups. For more than 10 areas, the characters, are simply repeated; that is, 11 through 20 use the same characters as 1 through 10, 21 through 30 use the same characters as 1 through 10, and so on.
VAR in the top line of a box indicates a variable-length segment. SXD in the top line of a box indicates that the segment has secondary index fields. If the segment is a sequential dependent segment (SDEP), SDEP is shown in the upper-right corner of the box. The segment code is placed in the bottom line of each box.
MULT in the top line of a box indicates that the segment has multiple secondary indexes.
Logical relationships for the segment box are indicated by the segment name of the logical parent or logical child and, where necessary, the name of the database that contains that segment. Dependent logical segments are not connected as physical segments are; rather, they appear first under their associated segment in a vertical row, one under another.
If the map is too wide or long to fit on a single page, the map is split and printed on as many contiguous pages as needed.
Differences among DBD, PSB, and ACB maps
Although the format of the four types of maps is similar, certain elements are different. The following list summarizes the differences between the DBD map and other types of maps:
- Differences in PSB maps
- PSB maps are similar to the DBD maps that the DBD Map function
generates. The following fields are different in DBD maps and PSB
maps:
DBDMAP OF dbdname in PSB-psbname
is shown in the header.- 2ND is shown in the upper-right corner of the box when the segment contains the secondary index specified in PROCSEQ of DB PCB in the PSB map.
- SXD is not shown in the PSB map.
- The processing options (PROCOPT values) used for the segment are shown at the lower-left corner of the box.
- Differences in ACB (PSB) maps
- ACB (PSB) maps are similar to the PSB maps that are generated
by the PSB Map function. The following fields are different between
PSB maps and ACB (PSB) maps:
- If the sensitive segment is a virtual child segment, information about this segment is not shown in the ACB (PSB) map.
- 2ND and SXD are not shown in the ACB (PSB) map.
- Differences in ACB (DBD) maps
- ACB (DBD) maps are similar to the DBD maps that are generated by the DBD Map function.