The -DC Lines tab is dedicated to the description of the CODASYL, DMSII, and TANDEM Database Blocks. You can declare the areas, call the records, and distribute them within the AREAS, call the SETS and describe them (name, label, parent, and child Segments).
You enter the Segment code which corresponds to the called record. When the Database Block is generated, this code is displayed after the 'RECORD' clause.
To modify the contents of this field, click Change. Then in the list which displays in a dialog box, select a Segment. You can also create a Segment.
This field can be used with an S-type line only.
Only used for IDMS ('D3', 'D4' types), DM4 ('M3' type) and DMS ('S3' type) subschemas.
On an R-type line, you can change the description of the selected record.
Depending on the value of the 'Type' of line selected, you enter:
You can select a subschema at the Block description level. To do so, on R-type lines, enter SS=n (with 'n' being the subschema number according to the definition). For an IDS2 (I3) subschema, it is possible to call an object (area, record, set) without redescribing it, by specifying: INCLUSION.
You enter the name of the physical file which supports the data. When the Database Block is generated, this name is displayed after the 'FILE IS' clause.
The -GG lines section is displayed when you enter or click a -DC description line. In this section, you can enter information to complete the description line.
In the -GG lines, you can modify the information contained in the Block Description lines before they are generated. Depending on the type of description line, lines are automatically displayed, in order to guide you when you enter the physical information of the Block. These lines are identified by 'VIRT' or 'GUID' in the last field of the table of the -GG lines. Collectively, these lines are called 'virtual' lines. The lines identified by 'VIRT' are generated. To modify these lines, you must override them and create new lines between beginning and end insertion lines. When you select a virtual line and click Override, the 'VIRT' or 'GUID' line is changed into a 'FromVIRT' or 'FromGUID' line. Then it can be modified. You can also edit the FromGUID and FromVIRT lines by selecting them and pressing the F2 key. You can create lines anywhere in the table. However if you want them to be taken into account at generation time, you must identify them with a G Type.
For more details on the generation lines, see the explanations about generation lines in Creating -GG lines associated with this page.