On 12/7/24 12:17, Igor Korot wrote:
Hi, Adrian,
On Sat, Dec 7, 2024 at 12:32 PM Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote:
On 12/7/24 09:59, Igor Korot wrote:
Hi, Adrian,
On Sat, Dec 7, 2024 at 11:18 AM Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote:
On 12/6/24 19:36, Igor Korot wrote:
Hi, All,
When my application starts up, ot creates some tables and insert records
in them.
When the app starts for the second time it should check if the tables
and the records in them are exist and skip the process.
Does this also apply to starts after the second time?
Yes, it does.
However, if the new table is created in the meantime - the new record
should be created, because it is not there yet.
What determines that a new table needs to be created and populated?
Consider the following scenario:
I did and it made me start twitching.
1. Program is installed.
2. Program is started for the first time.
3. My tables are created and populated
What distinguishes your tables from other users tables?
4. Program is executed.
5. User closes the program.
6.. Later on the user decides that there is a need
for another table (inside psql or any other client)
The above is where I started twitching.
How do you keep them out of your tables?
How do you get these changes to play nice with the existing structure?
7. Then the program starts for the second time.
At this time all my tables that were created will stay (courtesy
of CREATE TABLE IF NOT EXIST).
You are depending on folks not knowing about DROP TABLE and/or you
having thought out the permissions for access thoroughly.
All records that were there are staying unchanged.
INSERT/UPDATE against your tables is not a possibility?
However, for the table that was made in between the runs
will be added
Now if the program is installed on 2 different machines
and started simultaneously on both - I want to ensure that
only 1 set of tables is made and only 1 set of records in them
is available
I assume this means they are both pointing at the same instance of a
database?
This is the part that confuses me.
If you are going to allow ad hoc and at will changes how do you know
what is actually the correct change?
Now, the creation/population is done inside a transaction.
I'm not sure that a transaction is going to solve the issue I raised
above, it will just make one thing happen with no guarantee that it is
the correct outcome.
Are you talking about the front end that the user launches or the
backend that runs the database or something else?
Front-end.
This is a C++ app.
To me this is the tail wagging the dog. The thought of allowing users to
change the database structure and you dealing with it after the fact is
just disturbing to me.
Thank you.
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
