Database - good style searched
lazarus / 16-Databases

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Nicole · 2022-08-11 15:44

I have quite a lot of frames. Many of them are data sensitive.
I use Interbase 2.5 and made myself an unit DBModul.

What is good style to save where?
At the moment I put my datasource into the frame which it needs it.

What about datasets?
Is it a good idea to put it into the DBModul or into the Frame, which
uses it?

Can anybody hint me of "how many"?
I made a DB connection. Shall I leave it with "one" or shall I make
more of them?

What about transactions? Will every frame need its one, every query
its own?

What are the advantages or disadvantages in doing the one or the other
by Interbase?

At the moment I use Windows. In the long run I want to change to
Linux.

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HeavyUser · 2022-08-11 16:03

Quote from: Nicole on August 11, 2022, 05:44:27 pmI have quite a lot
of frames. Many of them are data sensitive.
I use Interbase 2.5 and made myself an unit DBModul.

What is good style to save where?
At the moment I put my datasource into the frame which it needs it.
That's the correct spot. a Datasource is used to quickly change the
source of data from one dataset to the next with out the need to
iterate through all the data edits on the frame.
Quote from: Nicole on August 11, 2022, 05:44:27 pmWhat about datasets?
Is it a good idea to put it into the DBModul or into the Frame, which
uses it?
Usually they belong in a datamodule and linked to the datasource, just
remember you can have a datamodule for each frame or any other kind of
grouping for your data you like, do not try to put everything in a
single datamodule. It will be problematic in the long run.

Quote from: Nicole on August 11, 2022, 05:44:27 pmCan anybody hint me
of "how many"?
I made a DB connection. Shall I leave it with "one" or shall I make
more of them?
One connection per thread is my way. Its easier to handle connections,
when you are using a concurrent users limited database.

Quote from: Nicole on August 11, 2022, 05:44:27 pm
What about transactions? Will every frame need its one, every query
its own?

I usually have a single transaction for all datasources except the
ones that are transaction sensitive ee financial transactions.
One transaction per frame should work fine too, just don't have long
running transactions its not good for your data.

Quote from: Nicole on August 11, 2022, 05:44:27 pm
What are the advantages or disadvantages in doing the one or the other
by Interbase?
Same as all transaction aware servers.

Once a transaction is committed/canceled the active datasets are
closed (use commit retaining).

Depending on transaction type, changes in one part of your application
will not be visible in an other transaction of the same application
until the first is committed and the second refreshed.
For more info please read up on firebird transactions.

Quote from: Nicole on August 11, 2022, 05:44:27 pm
At the moment I use Windows. In the long run I want to change to
Linux.
same thing regardless of the underline OS.