Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!mtxinu!rtech!davek From: davek@rtech.rtech.com (Dave Kellogg) Newsgroups: comp.databases Subject: Re: Attn: RTIngres GURUs Message-ID: <3003@rtech.rtech.com> Date: 19 Jun 89 12:49:53 GMT References: <449@sdcc15.ucsd.edu> <2981@rtech.rtech.com> Reply-To: davek@rtech.UUCP (Dave Kellogg) Organization: Relational Technology Inc, Alameda CA Lines: 34 In article <...> emuleomo@yes.rutgers.edu (Emuleomo) writes: > >a) I can't seem to be able to change the schema of a table once it is created. > For instance; I need to increase the size of a name fld from c15 to c20. > Also, if this can be done, will Ingres automatically rebuild the table > like Informix will do? > Once a table is created its data definition is fixed. The way to change the size of an attribute is to use the copy command to copy out the table, drop the table, recreate it, and then copy it back in. I know of a few people who have written simple front-ends to do this for you in a forms-based fashion (it's not terribly hard), and perhaps there is a net-lander who has such a program to post. There is a performance argument for this approach because it allows the data to remain clustered (i.e. adjacent attributes stored adjacently) in at least one sense of the word. With many table re-orgs, it's essentially "pay me now" (drop/recreate) or "pay me later" (with pointers to attributes stored in different locations from the base table, increasing I/O). >b) I am experimenting will QBF and VIFRED. Can you specify multi screen forms > in VIFRED and use it in QBF? Yes. See the section in the QBF manuals on "joindefs" where you create (or specify) the joins between relations and then QBF will create a default [multi-table] form that you can edit with VIFRED. (I am assuming you mean multi-table when you say multi-screen). Dave Kellogg Relational Technology New York City 212-952-1400