Schemas from ERA Diagrams

• A schema ER-diagram drawn with BDE is saved as a persistent database file. Thje latter can be automatically converted into meta-tables TT, TA and/or schema.sch via 96s523/bde2tt1/{b2t,t2s}.
  • A schema diagram drawn with another tool (e.g., PowerPoint or Idraw) must be manually edited into schema.sch. The latter cannot be automatically checked to see if it corresponds to the drawing.

• In either case, full attribute descriptions must be added at some point (by appending HA text to HN nodes in bde or by post-editing tables TT and TA or file schema.sch). Each attribute line in schema.sch must contain the 5-tuple <name, altname, format, iskey, description> .

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