/// <summary>
/// 执行查询文本并返回一个 <see cref="IDataReader"/>。
/// </summary>
/// <param name="queryCommand">查询命令。</param>
/// <param name="segment">数据分段对象。</param>
/// <param name="parameters">查询参数集合。</param>
/// <returns>一个 <see cref="IDataReader"/> 对象。</returns>
public virtual IDataReader ExecuteReader(IQueryCommand queryCommand, IDataSegment segment = null, ParameterCollection parameters = null, CommandBehavior?behavior = null)
{
Guard.ArgumentNull(queryCommand, nameof(queryCommand));
var connection = GetConnection(DistributedMode.Slave);
var command = new InternalDbCommand(CreateDbCommand(connection, queryCommand, parameters), _readerLocker);
try
{
var context = new CommandContext(this, command, segment, parameters);
HandleSegmentCommand(context);
return(HandleCommandExecuted(command, parameters, behavior ?? CommandBehavior.Default, (command, behavior) => command.ExecuteReader(behavior)));
}
catch (DbException exp)
{
throw HandleException(command, exp);
}
}
/// <summary>
/// 异步的，执行查询文本并返回一个 <see cref="IDataReader"/>。
/// </summary>
/// <param name="queryCommand">查询命令。</param>
/// <param name="segment">数据分段对象。</param>
/// <param name="parameters">查询参数集合。</param>
/// <param name="cancellationToken">取消操作的通知。</param>
/// <returns>一个 <see cref="IDataReader"/> 对象。</returns>
public async virtual Task <IDataReader> ExecuteReaderAsync(IQueryCommand queryCommand, IDataSegment segment = null, ParameterCollection parameters = null, CommandBehavior?behavior = null, CancellationToken cancellationToken = default)
{
Guard.ArgumentNull(queryCommand, nameof(queryCommand));
cancellationToken.ThrowIfCancellationRequested();
var connection = GetConnection(DistributedMode.Slave);
var command = new InternalDbCommand(CreateDbCommand(connection, queryCommand, parameters), _readerLocker);
try
{
var context = new CommandContext(this, command, segment, parameters);
await HandleSegmentCommandAsync(context, cancellationToken);
return(await HandleCommandExecutedAsync(command, parameters, behavior ?? CommandBehavior.Default,
(command, behavior, cancelToken) => command.ExecuteReaderAsync(behavior, cancelToken), cancellationToken));
}
catch (DbException exp)
{
throw await HandleExceptionAsync(command, exp, cancellationToken);
}
}
