Re: Insert records in the tavke only if they are not exist

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From: Igor Korot <[email protected]>
To: David G. Johnston <[email protected]>
Cc: pgsql-generallists.postgresql.org <[email protected]>
Subject: Re: Insert records in the tavke only if they are not exist
Date: Fri, 6 Dec 2024 22:02:22 -0600
Message-ID: <CA+FnnTwbmWABiTHxdc5sJ1ffWHoYkZuhzPqmfRmCJ7qLbEuAdQ@mail.gmail.com> (raw)
In-Reply-To: <CAKFQuwZmv_R-v5050iF9YynOPqzEzi8atj_w1Sjo6CaNBgZLPg@mail.gmail.com>
References: <CA+FnnTwcNNGsM_ck0ye1OsUN3Jjg94PzGMKRm--2ojJM_zVOMA@mail.gmail.com>
	<CAKFQuwZmv_R-v5050iF9YynOPqzEzi8atj_w1Sjo6CaNBgZLPg@mail.gmail.com>

Hi, Dvid,

On Fri, Dec 6, 2024, 9:55 PM David G. Johnston <[email protected]>
wrote:

> On Friday, December 6, 2024, Igor Korot <[email protected]> wrote:
>>
>> 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.
>>
>> Everything is good, except what if I have a connection from 2 different
>> users?
>>
>> I can run this inside transaction, but will this be enough? Will stating
>> transaction lock the DB and the second user will wait for transaction to
>> complete?
>>
>>
> Seems like letting the create table fail would be a reliable way to
> determine what is happening.  But this procedure overall just seems better
> avoided.  Can’t you just run an installer/updater separate from running the
> application?
>

Interesting idea bout the installer.
Except those tables will contain some additional info about the schema and
the application.

So if I create/remove new table, either in my app or from psql the record
will need to be inserted/deleted.

Thank you.


> David J.
>
>

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