/// <summary>
/// 创建实例。
/// </summary>
/// <param name="dataReader">ADO.NET DataReader对象。</param>
/// <param name="commandCache">ADO.NET Command 缓存对象。</param>
/// <param name="command">命令对象。</param>
/// <param name="commandText">当前查询命令语句。</param>
public AdoDataQueryReader(IDataReader dataReader, AdoCommandCache commandCache, ICommand command, string commandText)
: base(commandCache?.Connection, command, commandText)
{
_dataReader = dataReader;
_commandCache = commandCache;
command?.DataContext?.DisposableObjects?.Add(dataReader);
}
/// <summary>
/// 销毁DbCommand
/// </summary>
/// <param name="cache">DbCommandCache对象。</param>
public virtual void DestroyDbCommand(AdoCommandCache cache)
{
if (cache == null)
{
return;
}
DestroyDbCommand(cache.GetDbCommand(true));
DestroyConnection(cache.GetConnection(true));
cache.Connection = null;
cache.DbCommand = null;
}
/// <summary>
/// 创建DbCommand对象。
/// </summary>
/// <param name="commandText">命令文本</param>
/// <returns>返回DbCommandCache对象。</returns>
protected virtual AdoCommandCache CreateDbCommand(string commandText)
{
var connection = (IAdoConnection)DataContext?.Connections?.Take();
if (connection == null)
{
return(null);
}
IDbCommand dbCommand = null;
try {
connection.Open();
dbCommand = connection.DbConnection.CreateCommand();
//dbCommand.Connection = connection.DbConnection;
if (connection.Transaction.Working)
{
dbCommand.Transaction = connection.DbTransaction;
}
if (Timeout > 0)
{
dbCommand.CommandTimeout = Timeout;
}
dbCommand.CommandText = commandText;
FillDbCommandParameters(dbCommand);
var cache = new AdoCommandCache()
{
DbCommand = dbCommand, Connection = connection
};
var list = ThreadHelper.InterlockedGet(ref _list_commands);
if (list == null)
{
DestroyDbCommand(cache);
return(null);
}
list.Enqueue(cache);
return(cache);
} catch {
DestroyConnection(connection);
DestroyDbCommand(dbCommand);
throw;
}
}
/// <summary>
/// 创建ADO.NET 查询读取器实例。
/// </summary>
/// <param name="dataReader">ADO.NET DataReader对象。</param>
/// <param name="commandCache">ADO.NET Command 缓存对象。</param>
protected virtual AdoDataQueryReader CreateDataQueryReader(IDataReader dataReader, AdoCommandCache commandCache)
{
return(new AdoDataQueryReader(dataReader, commandCache, this, commandCache.DbCommand.CommandText));
}
/// <summary>
/// 执行查询，并且忽略返回值；如果期望用返回值当影响行数，建议最好用 ExecuteScalar 直接返回一个值更可靠一些。
/// </summary>
/// <param name="dbCommandCache">DbCommandCache对象。</param>
/// <returns>返回查询结果。</returns>
protected virtual int ExecuteNonQuery(AdoCommandCache dbCommandCache)
{
return(dbCommandCache?.DbCommand?.ExecuteNonQuery() ?? 0);
}
/// <summary>
/// 执行查询，并返回查询的第一条记录的第一个列。
/// </summary>
/// <param name="dbCommandCache">DbCommandCache对象。</param>
/// <returns>返回查询结果。</returns>
protected virtual object ExecuteScalar(AdoCommandCache dbCommandCache)
{
return(dbCommandCache?.DbCommand?.ExecuteScalar());
}
