Database

Database 类不通常通过McoSqlEngine 构造函数类实例化。**

以下列出了 Database 提供的方法：

beginTransaction

该方法通常通过 McoSqlSession 对象调用，以便在多个线程之间共享单个数据库连接：

    McoSql::Transaction* beginTransaction(
		McoSql::Allocator* allocator, 
        McoSql::Transaction::Mode mode, 
        int priority, 
        McoSql::Transaction::IsolationLevel level, 
        bool nolock = false
    );

示例

    McoMultithreadedSqlEngine engine;
    ...
     
    McoSqlSession session(&engine);
    Transaction* trans = session->database()->beginTransaction(Transaction::ReadWrite);
    session->executeStatement(trans, "update Member set balance=%i where id=%i",
                    fromBalance, idFrom);
    session->executeStatement(trans, "update Member set balance=%i where id=%i",
                    toBalance, idTo);
    trans->commit();
    trans->release();