/// <summary>
/// 执行command命令，并返回受影响行数
/// </summary>
/// <param name="command">command包含执行的命令</param>
/// <returns></returns>
public virtual int ExecuteNonQuery(DbCommand command)
{
using (DatabaseConnectionWrapper wrapper = GetOpenConnection())
{
PrepareCommand(command, wrapper.Connection);
return(DoExecuteNonQuery(command));
}
}
/// <summary>
/// 执行command命令并返回一个IDataReader，通过它可以读取结果
/// 调用者在调用完毕后，负责关闭IDataReader
/// </summary>
/// <param name="command"></param>
/// <returns></returns>
public virtual IDataReader ExecuteReader(DbCommand command)
{
using (DatabaseConnectionWrapper wrapper = GetOpenConnection())
{
PrepareCommand(command, wrapper.Connection);
IDataReader realReader = DoExecuteReader(command, CommandBehavior.Default);
return(CreateWrappedReader(wrapper, realReader));
}
}
//public virtual IDataReader ExecuteReader(DbCommand command)
//{
// using (DatabaseConnectionWrapper wrapper = GetOpenConnection())
// {
// PrepareCommand(command, wrapper.Connection);
// IDataReader realReader = DoExecuteReader(command, CommandBehavior.Default);
// }
//}
/// <summary>
/// 执行command命令，并返回查询所返回的结果集中第一行的第一列。忽略额外的列或行
/// </summary>
/// <param name="command"></param>
/// <returns></returns>
public virtual object ExecuteScalar(DbCommand command)
{
if (command == null)
{
throw new ArgumentNullException("command");
}
using (DatabaseConnectionWrapper wrapper = GetOpenConnection())
{
PrepareCommand(command, wrapper.Connection);
return(DoExecuteScalar(command));
}
}
public RefCountingDataReader(DatabaseConnectionWrapper connection, IDataReader innerReader)
: base(innerReader)
{
if (connection == null)
{
throw new ArgumentNullException("connection");
}
if (innerReader == null)
{
throw new ArgumentNullException("innerReader");
}
connectionWrapper = connection;
connectionWrapper.AddRef();
}
public static DatabaseConnectionWrapper GetConnection(Database db)
{
Transaction currentTransaction = Transaction.Current;
if (currentTransaction == null)
{
return(null);
}
Dictionary <string, DatabaseConnectionWrapper> connectionList;
DatabaseConnectionWrapper connection;
lock (transactionConnections)
{
if (!transactionConnections.TryGetValue(currentTransaction, out connectionList))
{
connectionList = new Dictionary <string, DatabaseConnectionWrapper>();
transactionConnections.Add(currentTransaction, connectionList);
currentTransaction.TransactionCompleted += OnTransactionCompleted;
}
}
lock (connectionList)
{
if (!connectionList.TryGetValue(db.ConnectionString, out connection))
{
DbConnection dbConnection = db.GetNewOpenConnection();
connection = new DatabaseConnectionWrapper(dbConnection);
connectionList.Add(db.ConnectionString, connection);
}
connection.AddRef();
}
return(connection);
}
/// <summary>
/// 创建一个被包装的DataReader对象，用来控制连接对象connection
/// </summary>
/// <param name="connection">Connectinon + refCount</param>
/// <param name="innerReader">被包装的reader</param>
/// <returns></returns>
protected virtual IDataReader CreateWrappedReader(DatabaseConnectionWrapper connection, IDataReader innerReader)
{
return(new RefCountingDataReader(connection, innerReader));
}
/// <summary>
/// 获取一个被包装的connection
/// 如果一个事务正在活动，这个connection对象将不会被disposed
/// </summary>
/// <returns></returns>
protected DatabaseConnectionWrapper GetOpenConnection()
{
DatabaseConnectionWrapper connection = TransactionScopeConnections.GetConnection(this);
return(connection ?? GetWrappedConnection());
}
