SQLite & concurrent access best practices

by Evgeny V » Sun, 09 May 2010 15:06:59 GMT


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 I believe you can provide the safe concurrency managment by using DB
transactions. Since you don't care about sequence between separate
activities you can run following snippet:

try
db.BeginTransaction
 db.RunCommand(insert or update etc.)
db.CommitTransaction
catch
db.RollbackTransaction

Evgeny





> >



SQLite & concurrent access best practices

by Thierry Legras » Mon, 10 May 2010 06:02:38 GMT


 Thank you both for your answers.

Are you sure using synchronized is enough inside the insert or update? I
also got exceptions in call to getReadableDatabase while another thread was
being writing so i don't think it would work. I am already using transaction
for DB write but it did not seem to make any changes.

The way i do each time i need to read/write/update DB is something like
that:

OnRead() {
 db = new myDBHelperClass();
 db.getReadableDatabase
 db.query(...)
 db.close()
}


OnWrite() {
 db = new myDBHelperClass();
 db.getWriteableDatabase
 db.beginTransaction
 db.insert(...)
 db.endTransaction
}

I was rather thinking of using a synchronized in OnRead and OnWrite, but has
such methods exists in differents Activities and Task, i am pretty reluctant
to do that.

I also so design were DB is open in Activity onCreate and closed in
onDestroy, but i guess i will not work when a task also needs write in the
DB while the DB is open by the activity.


2010/5/9 Evgeny V <evgen...@gmail.com>



(snip)

-- 
Thierry.

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