Merging Sub-schemas
A database converter (bde2sch, bde2SM, etc.) must combine an input data model or subschema with an output data model or subschema to define a common schema with separate input and output views.
Input and output schema.sch files must be concatenated before running chgen, which accepts exactly one schema.sch and emits tables TT + TA.
Concatenating independent metaschema tables derived from independent schema diagrams (e.g., two TT-tables with same TTid for distinct ttAbbrev’s) would require renaming all TTid keys of one subschema to avoid overlap. (Combining two bde diagram files into one would have the same problem and solution).