public override DbExpression Visit(DbGroupByExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbGroupExpressionBinding newInput = this.VisitGroupExpressionBinding(expression.Input);
this.EnterScope(newInput.Variable);
IList <DbExpression> newKeys = this.VisitExpressionList(expression.Keys);
this.ExitScope();
this.EnterScope(newInput.GroupVariable);
IList <DbAggregate> newAggs = this.VisitList <DbAggregate>(expression.Aggregates, this.VisitAggregate);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.Keys, newKeys) ||
!object.ReferenceEquals(expression.Aggregates, newAggs))
{
RowType groupOutput =
TypeHelpers.GetEdmType <RowType>(TypeHelpers.GetEdmType <CollectionType>(expression.ResultType).TypeUsage);
var boundKeys = groupOutput.Properties.Take(newKeys.Count).Select(p => p.Name).Zip(newKeys).ToList();
var boundAggs = groupOutput.Properties.Skip(newKeys.Count).Select(p => p.Name).Zip(newAggs).ToList();
result = CqtBuilder.GroupBy(newInput, boundKeys, boundAggs);
}
NotifyIfChanged(expression, result);
return(result);
}
internal DbGroupByExpression(TypeUsage collectionOfRowResultType,
DbGroupExpressionBinding input,
DbExpressionList groupKeys,
System.Collections.ObjectModel.ReadOnlyCollection <DbAggregate> aggregates)
: base(DbExpressionKind.GroupBy, collectionOfRowResultType)
{
Debug.Assert(input != null, "DbGroupExpression input cannot be null");
Debug.Assert(groupKeys != null, "DbGroupExpression keys cannot be null");
Debug.Assert(aggregates != null, "DbGroupExpression aggregates cannot be null");
Debug.Assert(groupKeys.Count > 0 || aggregates.Count > 0, "At least one key or aggregate is required");
_input = input;
_keys = groupKeys;
_aggregates = aggregates;
}
protected virtual DbGroupExpressionBinding VisitGroupExpressionBinding(DbGroupExpressionBinding binding)
{
DbGroupExpressionBinding result = binding;
if (binding != null)
{
DbExpression newInput = this.VisitExpression(binding.Expression);
if (!object.ReferenceEquals(binding.Expression, newInput))
{
result = CqtBuilder.GroupBindAs(newInput, binding.VariableName, binding.GroupVariableName);
this.RebindVariable(binding.Variable, result.Variable);
this.RebindVariable(binding.GroupVariable, result.GroupVariable);
}
}
return(result);
}
protected virtual void VisitGroupExpressionBindingPre(DbGroupExpressionBinding binding)
{
if (binding == null) throw new ArgumentException("binding");
VisitExpression(binding.Expression);
}
protected virtual void VisitGroupExpressionBindingPost(DbGroupExpressionBinding binding)
{
}
/// <summary>
/// Convenience method to visit the specified <see cref="DbGroupExpressionBinding"/>.
/// </summary>
/// <param name="binding">The DbGroupExpressionBinding to visit.</param>
/// <exception cref="ArgumentNullException"><paramref name="binding"/> is null</exception>
protected virtual void VisitGroupExpressionBindingPre(DbGroupExpressionBinding binding)
{
ADP1.CheckArgumentNull(binding, "binding");
VisitExpression(binding.Expression);
}
/// <summary>
/// Dumps a DbGroupExpressionBinding including its VariableName, GroupVariableName and DbExpression
/// </summary>
/// <param name="binding">The DbGroupExpressionBinding to dump</param>
internal void Dump(DbGroupExpressionBinding binding)
{
Begin("DbGroupExpressionBinding", "VariableName", binding.VariableName, "GroupVariableName", binding.GroupVariableName);
Begin("Expression");
Dump(binding.Expression);
End("Expression");
End("DbGroupExpressionBinding");
}
/// <summary>
/// Dumps a DbGroupExpressionBinding with the specified decoration
/// </summary>
/// <param name="binding">The DbGroupExpressionBinding to dump</param>
/// <param name="name">The decorating block name</param>
internal void Dump(DbGroupExpressionBinding binding, string name)
{
Begin(name);
Dump(binding);
End(name);
}
private void VisitGroupBinding(DbGroupExpressionBinding groupBinding)
{
_key.Append("GBVV");
VisitVariableName(groupBinding.VariableName);
_key.Append(",");
VisitVariableName(groupBinding.GroupVariableName);
_key.Append("=(");
groupBinding.Expression.Accept(this);
_key.Append(')');
}
// Utility translator method for lambda expressions that are part of group by. Given a lambda expression and its translated
// inputs, translates the lambda expression, assuming the input needs to be used as a grouping input
private DbExpression TranslateLambda(LambdaExpression lambda, DbExpression input, out DbGroupExpressionBinding binding)
{
input = NormalizeSetSource(input);
// create binding context for this lambda expression
string alias = _aliasGenerator.Next();
binding = input.GroupBindAs(alias, string.Format(CultureInfo.InvariantCulture, "Group{0}", alias));
return TranslateLambda(lambda, binding.Variable);
}
/// <summary>
/// Convenience method for post-processing after a DbGroupExpressionBinding has been visited.
/// </summary>
/// <param name="binding">The previously visited DbGroupExpressionBinding.</param>
protected virtual void VisitGroupExpressionBindingPost(DbGroupExpressionBinding binding)
{
}
/// <summary>
/// Convenience method to visit the specified <see cref="DbGroupExpressionBinding"/>.
/// </summary>
/// <param name="binding">The DbGroupExpressionBinding to visit.</param>
/// <exception cref="ArgumentNullException"><paramref name="binding"/> is null</exception>
protected virtual void VisitGroupExpressionBindingPre(DbGroupExpressionBinding binding)
{
EntityUtil.CheckArgumentNull(binding, "binding");
VisitExpression(binding.Expression);
}
/// <summary>
/// Convenience method to visit the specified <see cref="DbGroupExpressionBinding"/>.
/// </summary>
/// <param name="binding">The DbGroupExpressionBinding to visit.</param>
/// <exception cref="ArgumentNullException"><paramref name="binding"/> is null</exception>
protected virtual void VisitGroupExpressionBindingPre(DbGroupExpressionBinding binding)
{
//Contract.Requires(binding != null);
VisitExpression(binding.Expression);
}
