skinnysoli.blogg.se - Sqlite transaction rollback

#SQLITE TRANSACTION ROLLBACK UPDATE#

Transactions must be committed explicitly as Daniel said.

What bothers me is WHY does it not make any difference wether OR NOT I use trans.Rollback() in the catch-block.Ģ.) I am using the "using(resource)"-statement so what will happen if the transaction succeeds/commits to the state of the connection ? Will it be closed? Just concern that I do not do use the `using(var trans = new SQLiteTransaction()) That is ok because I used a transaction and the. The connection from the transaction needs to be shared among the dataprovider methods.ġ.) When a SQLiteException occurs because of inserting same primary keys "John" there is not inserted any of the "John" values. SQLiteCommand cmd2 = con.CreateCommand() Ĭmd2.CommandText = "INSERT INTO TEST(Name) VALUES('John')" Īs I use SQLite its best practice to use the SQLiteTransaction class for every executed sql command. SQLiteCommand cmd1 = con.CreateCommand() Ĭmd1.CommandText = "INSERT INTO TEST(Name) VALUES('John')" Var con = new Source=A:\TransactionScopeTest\TransactionTest.db Foreign Keys=ON") ĭo 2 sqlite inserts with same Primary Key value to raise an exception If the BEGIN IMMEDIATE operation succeeds, then no subsequent operations in that transaction will ever fail with an SQLITE_BUSY error.Create the Connection + Transaction: public SQLiteTransaction BeginTransaction() The BEGIN IMMEDIATE command goes ahead and starts a write transaction, and thus blocks all other writers.

If X starts a transaction that will initially only read but X knows it will eventually want to write and does not want to be troubled with possible SQLITE_BUSY_SNAPSHOT errors that arise because another connection jumped ahead of it in line, then X can issue BEGIN IMMEDIATE to start its transaction instead of just an ordinary BEGIN. For complex transactions that needs multiples writes (and reads) we create separate databases objects to ensure proper isolation Īccording to documentation it would be safe to start the transaction with 'begin immediate'.

#SQLITE TRANSACTION ROLLBACK UPDATE#

Simple update statements can also could be also achieved with a a shared database object as there is no risk of overlapping transactions (unless i miss something).

a single database object can be shared between readers.

For simple read operations you may not need multiples database objects.note that you can have separate needs following the operation you need I guess a feature suggestion at this point is to implement database object pooling with the above in mind. This is true if there is no dependence between executed statements otherwise (as in master-detail updates) you'll have to ensure proper order of execution If I am doing a transaction, I just create a new database object and throw it away after the transaction. This further leads me to conclude that db.serialize() itself is pointless with transactions. I don't think this is a good idea you'll have to ensure Transaction semantics yourself (specially Isolation) this is a burden the database should take care of (and can better handle) Yes, this could be achieved by some pool implementation (see below)Īlternatively i have to somehow track that there is no pending transaction So you have to use multiples connections to ensure proper isolation between concurrent should not use this database object for anything else other than this transaction If i understand properly, new sqlite3.Database(.) rely on the sqlite3_open_.() However, there is no isolation between operations that occur within the same database connection. SQLite provides isolation between operations in separate database connections. No Isolation Between Operations On The Same Database Connection This is the usual and expected behavior for SQL database systems. This is true regardless of whether the two database connections are in the same thread, in different threads of the same process, or in different processes.

Partial changes by the writer that have not been committed are invisible to the reader. If the same database is being read and written using two different database connections (two different sqlite3 objects returned by separate calls to sqlite3_open()) and the two database connections do not have a shared cache, then the reader is only able to see complete committed transactions from the writer. It seems impossible to ensure transaction properties with db.serialize only.Īs documentation say Isolation Between Database Connections