database - The reason that you might want two or more instances for same DB connection? -

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i trying think of scenario need more 1 instances of db connection.

normally, db connection 1 singleton object used everything. what's reason might want create instance of same class. (i read somewhere.)

trying understand this, 2 instances of db connections seem risky cause conflict when writing db. faster when reading? (maybe 1 reason?)

maybe db connection not example. can give me other scenario if know anywhere creating more 1 instance of singleton class make sense.

you may need more specific on local app/embedded db vs servers.

but, if have application server (iis, apache etc...) talks database server (sql server, oracle etc...), want concurrency , multiple connections active @ time. want concurrency since it's server handling many concurrent requests , sql servers should able handle that. serializing database activity on server catastrophic.

concerning db connections, db access technologies, offer connection pooling. open connection, work , close. acquires , releases connections pool don't have recreated.

re: "two instances of db connections seem risky cause conflict when writing db"

most database servers offer control when dealing concurrency. example sql server, have locking , isolation levels


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