私の仕事は最近使い始めましたが、素晴らしいものでしたが、単一のクエリから複数の結果グリッドを pocos に処理できる機能PetaPocoを見逃していました。Dapper
その結果、PetaPoco以下に示すように独自の実装を作成しましたが、独自に作成して共有したい人はいますか?
この機能を見逃している人が他にもいるのではないかと思いました。
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1 に答える
13
編集 (2016-06-27): PetaPocoの バージョン5.1.181 (執筆時点では現在ベータ版) の時点で、この機能は PetaPoco NuGet パッケージで利用できるようになりました。
情報
この機能を実装するためのインスピレーションとして Dapper のソースを使用したので、類似点はそれによるものです。
これにより、PetaPoco.cs ファイルが直接変更されますが、最初のコメントから判断すると、おそらく行うべきではありません。
このコードはテスト済みですが、十分にテストされているわけではありません。適切な注意を払ってください!
使用法
private string _sql = @"SELECT * FROM WebOrders w INNER JOIN Address a ON a.Id = w.DeliveryAddressId WHERE OrderId = @0
SELECT * FROM WebOrderLines WHERE OrderId = @0 AND CustomerId = @1
SELECT * FROM ContactDetails WHERE CustomerId = @1";
private readonly Database _db = new Database("Shop");
var result = new WebOrder();
using (var multi = _db.QueryMultiple(_sql, 12345, 67890))
{
result = multi.Read<WebOrder, Address, WebOrder>((w, a) => { w.Address = a; return w; }).Single();
result.OrderLines = multi.Read<WebOrderLines>().ToList();
result.ContactDetails = multi.Read<ContactDetails>().ToList();
}
return result;
変更点 - PetaPoco (コア) v.5.0.1
クラスPetaPoco.Database内に以下を追加します。
#region operation: Multi-Result Set
/// <summary>
/// Perform a multi-results set query
/// </summary>
/// <param name="sql">An SQL builder object representing the query and it's arguments</param>
/// <returns>A GridReader to be queried</returns>
public GridReader QueryMultiple(Sql sql)
{
return QueryMultiple(sql.SQL, sql.Arguments);
}
/// <summary>
/// Perform a multi-results set query
/// </summary>
/// <param name="sql">The SQL query to be executed</param>
/// <param name="args">Arguments to any embedded parameters in the SQL</param>
/// <returns>A GridReader to be queried</returns>
public GridReader QueryMultiple(string sql, params object[] args)
{
OpenSharedConnection();
GridReader result = null;
var cmd = CreateCommand(_sharedConnection, sql, args);
try
{
var reader = cmd.ExecuteReader();
result = new GridReader(this, cmd, reader);
}
catch (Exception x)
{
if (OnException(x))
throw;
}
return result;
}
#endregion
ルート レベル (名前空間: PetaPoco ) に以下を追加します。
#region Multi-Results Set GridReader
public class GridReader : IDisposable
{
private IDataReader _reader;
private IDbCommand _command;
private readonly Database _db;
/// <summary>
/// The control structure for a multi-result set query
/// </summary>
/// <param name="database"></param>
/// <param name="command"></param>
/// <param name="reader"></param>
internal GridReader(Database database, IDbCommand command, IDataReader reader)
{
_db = database;
_command = command;
_reader = reader;
}
#region public Read<T> methods
/// <summary>
/// Reads from a GridReader, returning the results as an IEnumerable collection
/// </summary>
/// <typeparam name="T">The Type representing a row in the result set</typeparam>
/// <returns>An enumerable collection of result records</returns>
public IEnumerable<T> Read<T>()
{
return SinglePocoFromIDataReader<T>(_gridIndex);
}
/// <summary>
/// Perform a multi-poco read from a GridReader
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<T1> Read<T1, T2>()
{
return MultiPocoFromIDataReader<T1>(_gridIndex, new Type[] {typeof (T1), typeof (T2)}, null);
}
/// <summary>
/// Perform a multi-poco read from a GridReader
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <typeparam name="T3">The third POCO type</typeparam>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<T1> Read<T1, T2, T3>()
{
return MultiPocoFromIDataReader<T1>(_gridIndex, new Type[] {typeof (T1), typeof (T2), typeof (T3)}, null);
}
/// <summary>
/// Perform a multi-poco read from a GridReader
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <typeparam name="T3">The third POCO type</typeparam>
/// <typeparam name="T4">The forth POCO type</typeparam>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<T1> Read<T1, T2, T3, T4>()
{
return MultiPocoFromIDataReader<T1>(_gridIndex,
new Type[] {typeof (T1), typeof (T2), typeof (T3), typeof (T4)}, null);
}
/// <summary>
/// Perform a multi-poco query
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <typeparam name="TRet">The type of objects in the returned IEnumerable</typeparam>
/// <param name="cb">A callback function to connect the POCO instances, or null to automatically guess the relationships</param>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<TRet> Read<T1, T2, TRet>(Func<T1, T2, TRet> cb)
{
return MultiPocoFromIDataReader<TRet>(_gridIndex, new Type[] {typeof (T1), typeof (T2)}, cb);
}
/// <summary>
/// Perform a multi-poco query
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <typeparam name="T3">The third POCO type</typeparam>
/// <typeparam name="TRet">The type of objects in the returned IEnumerable</typeparam>
/// <param name="cb">A callback function to connect the POCO instances, or null to automatically guess the relationships</param>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<TRet> Read<T1, T2, T3, TRet>(Func<T1, T2, T3, TRet> cb)
{
return MultiPocoFromIDataReader<TRet>(_gridIndex, new Type[] {typeof (T1), typeof (T2), typeof (T3)}, cb);
}
/// <summary>
/// Perform a multi-poco query
/// </summary>
/// <typeparam name="T1">The first POCO type</typeparam>
/// <typeparam name="T2">The second POCO type</typeparam>
/// <typeparam name="T3">The third POCO type</typeparam>
/// <typeparam name="T4">The forth POCO type</typeparam>
/// <typeparam name="TRet">The type of objects in the returned IEnumerable</typeparam>
/// <param name="cb">A callback function to connect the POCO instances, or null to automatically guess the relationships</param>
/// <returns>A collection of POCO's as an IEnumerable</returns>
public IEnumerable<TRet> Read<T1, T2, T3, T4, TRet>(Func<T1, T2, T3, T4, TRet> cb)
{
return MultiPocoFromIDataReader<TRet>(_gridIndex,
new Type[] {typeof (T1), typeof (T2), typeof (T3), typeof (T4)}, cb);
}
#endregion
#region PocoFromIDataReader
/// <summary>
/// Read data to a single poco
/// </summary>
/// <typeparam name="T">The type representing a row in the result set</typeparam>
/// <param name="index">Reader row to be read from the underlying IDataReader</param>
/// <returns></returns>
private IEnumerable<T> SinglePocoFromIDataReader<T>(int index)
{
if (_reader == null)
throw new ObjectDisposedException(GetType().FullName, "The data reader has been disposed");
if (_consumed)
throw new InvalidOperationException(
"Query results must be consumed in the correct order, and each result can only be consumed once");
_consumed = true;
var pd = PocoData.ForType(typeof (T));
try
{
while (index == _gridIndex)
{
var factory =
pd.GetFactory(_command.CommandText, _command.Connection.ConnectionString, 0, _reader.FieldCount,
_reader) as Func<IDataReader, T>;
while (true)
{
T poco;
try
{
if (!_reader.Read())
yield break;
poco = factory(_reader);
}
catch (Exception x)
{
if (_db.OnException(x))
throw;
yield break;
}
yield return poco;
}
}
}
finally // finally so that First etc progresses things even when multiple rows
{
if (index == _gridIndex)
{
NextResult();
}
}
}
/// <summary>
/// Read data to multiple pocos
/// </summary>
/// <typeparam name="TRet">The type of objects in the returned IEnumerable</typeparam>
/// <param name="index">Reader row to be read from the underlying IDataReader</param>
/// <param name="types">An array of Types representing the POCO types of the returned result set.</param>
/// <param name="cb">A callback function to connect the POCO instances, or null to automatically guess the relationships</param>
/// <returns>A collection of POCO's as an IEnumerable</returns>
private IEnumerable<TRet> MultiPocoFromIDataReader<TRet>(int index, Type[] types, object cb)
{
if (_reader == null)
throw new ObjectDisposedException(GetType().FullName, "The data reader has been disposed");
if (_consumed)
throw new InvalidOperationException(
"Query results must be consumed in the correct order, and each result can only be consumed once");
_consumed = true;
try
{
var cmd = _command;
var r = _reader;
var factory = MultiPocoFactory.GetFactory<TRet>(types, cmd.Connection.ConnectionString, cmd.CommandText,
r);
if (cb == null)
cb = MultiPocoFactory.GetAutoMapper(types.ToArray());
bool bNeedTerminator = false;
while (true)
{
TRet poco;
try
{
if (!r.Read())
break;
poco = factory(r, cb);
}
catch (Exception x)
{
if (_db.OnException(x))
throw;
yield break;
}
if (poco != null)
yield return poco;
else
bNeedTerminator = true;
}
if (bNeedTerminator)
{
var poco = (TRet) (cb as Delegate).DynamicInvoke(new object[types.Length]);
if (poco != null)
yield return poco;
else
yield break;
}
}
finally
{
if (index == _gridIndex)
{
NextResult();
}
}
}
#endregion
#region DataReader Management
private int _gridIndex;
private bool _consumed;
/// <summary>
/// Advance the IDataReader to the NextResult, if available
/// </summary>
private void NextResult()
{
if (!_reader.NextResult()) return;
_gridIndex++;
_consumed = false;
}
/// <summary>
/// Dispose the grid, closing and disposing both the underlying reader, command and shared connection
/// </summary>
public void Dispose()
{
if (_reader != null)
{
if (!_reader.IsClosed && _command != null) _command.Cancel();
_reader.Dispose();
_reader = null;
}
if (_command != null)
{
_command.Dispose();
_command = null;
}
_db.CloseSharedConnection();
}
#endregion
}
#endregion
この変更をPetaPoco v5 ブランチに提出しましたが、ここに投稿すると人々が何らかの利益を得るかもしれないと考えました。
于 2013-10-24T20:49:42.207 に答える