Re: INFORMIX-SE and databases

->From: bsimmons@teal.csn.org (Brian Simmons) ->Subject: INFORMIX-SE and databases ->Date: Thu, 9 Dec 1993 03:13:10 GMT ->Reply-To: bsimmons@teal.csn.org (Brian Simmons) ->Organization: Colorado SuperNet, Inc. -> ->I recieved a few item from Informix describing the SE system, and I was ->wondering about databases: It says I can have only 1 database open at a time? ->That sounds like some limitation. I assume I can have as many tables (which ->are files, right?) open as I want? No limit of tables per database? .. [1] ->Are there any perfomance considerations for putting all my tables in one ->database, even if they are unrelated? What is the overhead of opening a ->database? I assume I can do something like: -> ->open database ->select data ->close database ->open second_db ->select more data ->close second_db -> ->But that will take up alot of memory right? Load the whole of the first .. [2] ->group, then the second. The way I would like to write it is to load ->one record (row?) from the DB, get more data from another table and then ->output it or whatever. For that, I'd need both tables in one database? .. [3] ->-- ->Brian Simmons, Denver,Colorado,USA. - bsimmons@csn.org *On an Amiga!* [1] Yes, you can have only one database open at a time under SE. That is not really a problem, since you can have almost any number of tables in a DB. The limits on number of tables are outrageously LARGE. Each table is assigned an internal integer ID number starting with 100. (System tables have numbers < 100.) So you are limited by the integer size; but this allows for > 2 BILLION tables. In SE, this integer is also used to make the names of files containing your tables unique. If you have an 'employee' table and an 'employee_benefits' table, the files will be named something like 'employe101.dat' and 'employe102.dat'. Based on this scheme, you MIGHT have name collisions when you get over 1000 tables, IF the file name only uses the last 3 digits of the number. Maybe it uses all 4 digits; I don't know, I've never needed more than about 90 tables in my databases. I have heard of database with several hundred tables. [2] Opening a database does not impose a lot of overhead. It is mostly establishing a connection between the client program front-end and the database server process back-end. Some stuff is sent back and forth, but not the "whole of" the database. [3] Yep, multiple tables in one database is the way to go. Regards, Alan ___________________________ ______________________| R. Alan Popiel |__________________________ \\ Internet: | Martin Marietta, SLS | / \\ alan@den.mmc.com | P.O. Box 179, M/S 3810 | Std disclaimers apply. / )Voice: | Denver, CO 80201-0179 USA | ( / 303-977-9998 |___________________________| (But you knew that!) \\ /________________________) (____________________________\\