Re: graphic display of relationships?
Forwarded from: Greg Bryan <gbryan@ssf-sys.DHL.COM> -- Walt Hultgren Internet: walt@rmy.emory.edu (IP 128.140.8.1) Emory University Alternates: walt%rmy.emory.edu@uunet.uu.net 954 Gatewood Road, NE walt%rmy.emory.edu@wsmr-simtel20.army.mil Atlanta, GA 30329 USA BITNET: walt@EMORY Voice: +1 404 727 0648 UUCP: {...,gatech,rutgers,uunet}!emory!rmy!walt --- Header ------------------------------------------------------------------- > From gbryan@ssf-sys.DHL.COM Wed Jun 5 17:50:14 1991 > Received: from relay1.UU.NET by > rmy.rmy.emory.edu (5.59/2.14.EUCC-MathCS) via SMTP > id AA07905 ; Wed, 5 Jun 91 17:50:08 EST > Received: from gateway.DHL.COM by relay1.UU.NET with SMTP > (5.61/UUNET-internet-primary) id AA04258; Wed, 5 Jun 91 17:49:35 -0400 > Received: from dhlmis.ssf-sys.dhl.com by gateway.DHL.COM > id aa16783; Wed, 5 Jun 91 14:47:08 PDT > Received: by dhlmis.ssf-sys.DHL.COM > (5.61/1.8) id AA22349; Wed, 5 Jun 91 14:45:58 -0700 > From: Greg Bryan <gbryan@ssf-sys.DHL.COM> > Date: Wed, 5 Jun 91 14:45:57 PDT > X-Mailer: ELM [version 2.3 PL11] > Message-Id: <9106051447.aa16783@gateway.DHL.COM> --- Message ------------------------------------------------------------------ > > Does anyone have tools to produce a (semi-)graphical display > of the relationships in a database from the system catalogs? > Actually, any type of description (text, even) would be fine. > If no such beastie exists, what kind of interest would there be for one? > What kind of information would be desired, what kind of format, etc. ???? > > John Ackley <john@equi.com> > The only problem with this is that there is no information in the system catalogs about relationships between tables. It might be possible to deduce the existence of a primary key if there is a single unique index on a table - but you'd really only be guessing. There is no way at all to spot a foreign key, or to determine what primary key it might join. This kind of thing could be supported by extending the definitions of the system tables (ie. adding some new system tables & maintaining them). Incidentally, for producing Entity Relationship Diagrams, ERwin (from Logic Works, Princeton, NJ) is a reasonable, PC based tool. This tool is based on (and includes a good explanation of) the IDEF1X data modeling notation. IDEF1X is a standard that was published by the US Air Force in 1985. This is a good place to start for information about kinds of information & format for data models. The IDEF1X standard is available from the US Govt: National Technical Information Service phone: 703-487-4650 CATALOG #: NTIS ADA 181952 Another good source of information is: "Handbook of Relational Database Design" by Candace C. Fleming & Barbara von Halle Addison-Wesley, 1989 Greg Bryan Data Administrator DHL Systems Inc. San Mateo, CA 415-574-4197 gbryan@ssf-sys.dhl.com --- End of Message -----------------------------------------------------------