huelsman@infbs.UUCP (Klaus Huelsmann) (02/07/90)
Dear net,
We are running an experimental database design system based on the ER-model.
It provides facilities for specifying ER-schemas and transforming them to
relational database schemas. The relational schemas are installed on the
INGRES database system version 6.2. Now we are interested in generating auto-
matically INGRES forms according to the underlying ER-schema where the forms
are some 'INGRES representation' of the entity-relationship schema. We think
of forms for inserting, retrieving, deleting and updating entities or
relationships including some constraint checking on the attributes.
The questions are:
1) How can we create INGRES forms by use of an application program?
2) For which classes of integrity constraints given in some abstract
way in the design environment can we generate the corresponding
constraint checks for the forms?
Thanks in advance.
Klausjkrueger@dgis.dtic.dla.mil (Jon) (02/11/90)
huelsman@infbs.UUCP (Klaus Huelsmann) writes: > 1) How can we create INGRES forms by use of an application program? INGRES forms are stored in the database as tables. (In V5, those tables are fdframes, fdfields, fdtrim, and iicompform.) So if you place the right values in the tables, which an application program can certainly do (subject to "update system catalogs" permissions), presumably you got yourself a form. Then you use the forms run time system as with any other form. Bingo! Instant default forms! You could write your own QBF! Your own VIFRED! And stay compatible with every Ingres-supplied tool! Except: the system catalogs are documented to the point where you can, say, query fdfields to get the average number of fields per form. They are NOT documented to the point where you can safely manipulate them. For instance, if you add rows to fdfields or fdtrim, you may need to update an existing row in fdframes, say to change the value in maxcol or maxlin. However, this could change. Ingres may choose at some future time to document the system catalogs more fully. Hint, hint :-) -- Jon -- Jonathan Krueger jkrueger@dtic.dla.mil uunet!dgis!jkrueger The Philip Morris Companies, Inc: without question the strongest and best argument for an anti-flag-waving amendment.