[Database]SQLite3 Transaction [事务处理]

>> Transaction

Begin Transaction

Commit Transaction

Rollback Transaction

>> No Nest Transaction

Use SavePoint instead.

SAVEPOINTs are a method of creating transactions, similar to BEGIN and COMMIT, except that the SAVEPOINT and RELEASE commands are named and may be nested.

Create SAVEPOINT

Release

>> 三种Transaction类型

Deferred/Immediate/Exclusive

    // From My Sqlite3 wrapper: SqliteDataTypes

    ///<summary>
    /// Three types of transactions in SQLite: Deferred, Immediate and Exclusive
    /// The default transaction behavior is deferred.
    ///<summary>
    enum TransactionType
    {
        ///<summary>
        /// Deferred Transaction is the default transaction in SQLite.
        /// Statement can be "BEGIN DEFERRED" or "BEGIN".
        /// Deferred means that no locks are acquired on the database until the database is first accessed.
        /// Thus with a deferred transaction, the BEGIN statement itself does nothing to the filesystem.
        /// Locks are not acquired until the first read or write operation.
        /// The first read operation against a database creates a SHARED lock
        /// and the first write operation creates a RESERVED lock.
        /// Because the acquisition of locks is deferred until they are needed,
        /// it is possible that another thread or process could create a separate transaction
        /// and write to the database after the BEGIN on the current thread has executed.
        ///</summary>
        kDeferred  = 0,

        ///<summary>
        /// Deferred Transaction is the default transaction in SQLite.
        /// Statement is "BEGIN IMMEDIATE".
        /// If the transaction is immediate, then RESERVED locks are acquired on all databases
        /// as soon as the BEGIN command is executed, without waiting for the database to be used.
        /// After a BEGIN IMMEDIATE, it is guaranteed that no other thread or process
        /// will be able to write to the database or do a "BEGIN IMMEDIATE" or "BEGIN EXCLUSIVE".
        /// Other processes can continue to read from the database.
        ///</summary>
        kImmediate = 1,

        ///<summary>
        /// Statement is "BEGIN EXCLUSIVE".
        /// An exclusive transaction causes EXCLUSIVE locks to be acquired on all databases.
        /// After a BEGIN EXCLUSIVE, no other database connection
        /// except for read_uncommitted connections will be able to read the database
        /// and no other connection without exception will be able to write the database
        /// until the transaction is complete. 
        ///<summary>
        kExclusive = 2
    };

>>官方文档

http://www.sqlite.org/lang_transaction.html

http://www.sqlite.org/lang_savepoint.html