Levels cross-reference files
The levels cross-reference files, qvlvmn, define the relationship between the data at levels m and n. The values of m and n represent each level’s position in the levels file. For example, if your database has the following structure:
lev1
|
--------------
| |
lev2a lev2b
| |
--------- |
| | |
lev3a lev3b lev3c
|
lev4a
and your levels file contains the lines:
lev1 cards=1
lev2a cards=2 <lev1
lev2b cards=3 <lev1
lev3a cards=4 <lev2a
lev3b cards=5 <lev2a
lev3c cards=6 <lev2b
lev4a cards=7 <lev3b
Quantum creates the following cross-reference files:
qvlv12 qvlv13 qvlv14 qvlv15 qvlv16 qvlv17
qvlv24 qvlv25 qvlv27 qvlv36 qvlv57
The file qvlv12 defines the relationship between lines 1 and 2 — that is, lev1 and lev2a, the file qvlv27 defines the link between lines 2 and 7 — that is, lev2a and lev4a, and so on. There is no file qvlv26, for example, because lev3c is not related to lev2a.
If you change the order of the levels in this file, the names of the cross-reference files are different even though the information they contain is the same. If the levels file is:
lev1 cards=1
lev2a cards=2 <lev1
lev3a cards=4 <lev2a
lev3b cards=5 <lev2a
lev4a cards=7 <lev3b
lev2b cards=3 <lev1
lev3c cards=6 <lev2b
Quantum create the following cross-reference files:
qvlv12 qvlv13 qvlv14 qvlv15 qvlv16 qvlv17
qvlv23 qvlv24 qvlv25 qvlv45 qvlv67
See also