Hello! The question of multiple tables or one table is a fundamental one. If you need to combine data from multiple tables to do your reports, especially if the table structure for each sensor is identical, this could be a nightmare for you. OTOH, if you are only reporting on only one sensor at a time, then multiple tables would make sense.
I think, you should not worry about table size or the number of records as long as each record is not very large. Keep your database as SQL compliant as possible and let the database engine work for you. Having one table for all data is easier if you have an unknown number of sensors to deal with. It is easier to add a sensor ID, then create a new table each time you add a sensor. Just my 2 cents... Tom Nesler Live long!... Code Well!... and Prosper!... V -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chris Stebbing Sent: Wednesday, June 11, 2008 1:29 AM To: Delphi DB List Subject: Database Design Question Hi All, I have a question on database design if I may. The application that I will be working on is an industrial one where we will be logging data from a number of different sensors all at differing rates. The "current" data value is used to initiate actions and is always held in memory, but past data is most commonly graphed regularly. By far the largest amount of data is generated by logging these sensors, and the most common use for this data is simply graphing. An installation could range anywhere from 5 sensors to 100 sensors. The main question I have is whether it would be better to have all these sensors log into one table, or have them log into a separate table per sensor. The amount of data can build up quite an amount over time, and filtering one large table (or querying one large table) takes an amount of time. Having the data already separated by sensor would be a huge head start. Thanks for any comments and my apologies if this question is out of line here. Regards, Chris. _______________________________________________ Delphi-DB mailing list Delphi-DB@elists.org http://lists.elists.org/cgi-bin/mailman/listinfo/delphi-db
