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using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Common;
using System.IO;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using System.Data.SqlClient;
using System.Diagnostics;
using Signum.Utilities.Reflection;
using Signum.Utilities.DataStructures;
using Signum.Utilities;
using Signum.Utilities.ExpressionTrees;
using Signum.Engine;
using System.Data;
namespace Signum.Engine.Linq
{
/// <summary>
/// Stateless query provider
/// </summary>
public class DbQueryProvider : QueryProvider
{
public static readonly DbQueryProvider Single = new DbQueryProvider();
private DbQueryProvider()
{
}
public override string GetQueryText(Expression expression)
{
return this.Translate(expression).CommandText;
}
MethodInfo mi = typeof(DbQueryProvider).GetMethod("ExecutePrivateUnique", BindingFlags.NonPublic | BindingFlags.Instance);
public override object ExecutePrivate<S>(Expression expression)
{
ITranslateResult tr = this.Translate(expression);
if (tr.UniqueFunction == UniqueFunction.SingleIsZero || tr.UniqueFunction == UniqueFunction.SingleGreaterThanZero)
{
IEnumerable<int> reader = ExecuteReader<int>((TranslateResult<int>)tr, null);
int count = reader.Single();
if (tr.UniqueFunction == UniqueFunction.SingleGreaterThanZero)
return count > 0;
else
return count == 0;
}
else
{
IEnumerable<S> reader = ExecuteReader<S>((TranslateResult<S>)tr, null);
if (tr.UniqueFunction.HasValue)
switch (tr.UniqueFunction.Value)
{
case UniqueFunction.First: return reader.First();
case UniqueFunction.FirstOrDefault: return reader.FirstOrDefault();
case UniqueFunction.Single: return reader.Single();
case UniqueFunction.SingleOrDefault: return reader.SingleOrDefault();
default:
throw new InvalidOperationException();
}
else
if (tr.HasFullObjects)
return reader.ToList();
else
return reader;
}
}
internal IEnumerable<T> ExecuteReader<T>(TranslateResult<T> tr, IProjectionRow pr)
{
SqlPreCommandSimple command = new SqlPreCommandSimple(tr.CommandText, tr.GetParameters(pr).ToList());
DataTable dt = Executor.ExecuteDataTable(command);
ProjectionRowEnumerator<T> enumerator = new ProjectionRowEnumerator<T>(dt, tr.ProjectorExpression, this, tr.HasFullObjects, pr, tr.Alias);
return new ProjectionRowReader<T>(enumerator).ToList();
}
private ITranslateResult Translate(Expression expression)
{
Expression partialEval = Evaluator.PartialEval(expression);
Expression simplified = OverloadingSimplifier.Simplify(partialEval);
ProjectionExpression binded = (ProjectionExpression)QueryBinder.Bind(simplified);
ProjectionExpression projCleaned = (ProjectionExpression)ProjectionCleaner.Clean(binded);
ProjectionExpression ordered = OrderByRewriter.Rewrite(projCleaned);
ProjectionExpression aggregate = AggregateOptimizer.Optimize(ordered);
ProjectionExpression replaced = AliasProjectionReplacer.Replace(aggregate);
ProjectionExpression columnCleaned = (ProjectionExpression)UnusedColumnRemover.Remove(replaced);
ProjectionExpression optimized = SingleCellOptimizer.Optimize(columnCleaned);
ProjectionExpression subqueryCleaned = (ProjectionExpression)RedundantSubqueryRemover.Remove(optimized);
ITranslateResult result = TranslatorBuilder.Build((ProjectionExpression)subqueryCleaned, ImmutableStack<string>.Empty);
return result;
}
}
}
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I'm Computer Scientist, one of the founders of Signum Software, and the lead developer behind Signum Framework.
www.signumframework.com
I love programming in C#, Linq, Compilers, Algorithms, Functional Programming, Computer Graphics, Maths...