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From: "David G. Johnston" <david.g.johnston@gmail.com>
Date: Fri, 6 Dec 2024 20:55:00 -0700
Message-ID: <CAKFQuwZmv_R-v5050iF9YynOPqzEzi8atj_w1Sjo6CaNBgZLPg@mail.gmail.com>
Subject: Re: Insert records in the tavke only if they are not exist
To: Igor Korot <ikorot01@gmail.com>
Cc: "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
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On Friday, December 6, 2024, Igor Korot <ikorot01@gmail.com> 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=E2=80=99t you just run an installer/updater separate from run=
ning the
application?

David J.

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On Friday, December 6, 2024, Igor Korot &lt;<a href=3D"mailto:ikorot01@gmai=
l.com">ikorot01@gmail.com</a>&gt; wrote:<blockquote class=3D"gmail_quote" s=
tyle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div=
 dir=3D"auto"><div dir=3D"auto">When my application starts up, ot creates s=
ome tables and insert records in them.</div><div dir=3D"auto"><br></div><di=
v dir=3D"auto">When the app starts for the second time it should check if t=
he tables and the records in them are exist and skip the process.</div><div=
 dir=3D"auto"><br></div><div dir=3D"auto">Everything is good, except what i=
f I have a connection from 2 different users?</div><div dir=3D"auto"><br></=
div><div dir=3D"auto">I can run this inside transaction, but will this be e=
nough? Will stating transaction lock the DB and the second user will wait f=
or transaction to complete?</div><div dir=3D"auto"><br></div></div></blockq=
uote><div><br></div><div>Seems like letting the create table fail would be =
a reliable way to determine what is happening.=C2=A0 But this procedure ove=
rall just seems better avoided.=C2=A0 Can=E2=80=99t you just run an install=
er/updater separate from running the application?</div><div><br></div><div>=
David J.</div><div><br></div>

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