[cad-linux] Re: database cad system
- From: "Brian Johnson" <bjohnson@xxxxxxxxxxxxxxxxxxxxxx>
- To: cad-linux@xxxxxxxxxxxxx
- Date: Tue, 24 Jun 2003 13:51:46 +0000
Eric Wilhelm (ewilhelm@xxxxxxxxxxxxx) wrote:
>
>> The following was supposedly scribed by
>> Brian Johnson
>> on Monday 23 June 2003 11:01 am:
>
>>use DBI;
>
>Yes, thanks. It looks like this will be a very useful tool in my future
>projects. I know very little about SQL right now (except for a
>roughly-how-it-works and that it is a networked database), so I've got quite
>a bit of work to do in that respect. It doesn't seem really well-suited to
>geometry, but it looks like a "front end" would allow you to more easily
>manipulate objects. What about binary data? Can you store a float in the
>table without storing it as a string (and could you match on the binary
>data?)
Most dbs support a variety of data types. char, int, and float are the most
common
>It seems that the real trick here is going to be getting a modeling or
>drafting (or both) package to "play nice" with the sql (maybe via vba, but
>I'd rather steer clear of that route unless it is unavoidable).
>
>Are there any database servers that allow data to be recalculated based on
>other updated data, or do these relationships have to be handled by an
>external program (maybe a change to one field would initiate a call to an
>external process?)
>
>--Eric
All SQL dbs allow you to add (INSERT) a record and change an existing record
(UPDATE). So you could do a INSERT and then an UPDATE on another record.
Many dbs allow some kind of grouping so that if you are doing a group of SQL
statements it rolls back to where it started if one of the statements results
in an
error (I don't think MySQL does this and is one reason why people switch to
using
postgreSQL)
You could also use triggers and stored procedures in some dbs but then the
system
becomes more dependant on one db since these change quite a bit from on db to
another
--
Brian Johnson
* This is where my witty signature line would be if I bothered to edit this
line :) *
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