public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
_xmlWriter.WriteStartElement("caseExpression");
WriteTypeAttribute(expression.ExpressionType);
if (expression.InputExpression != null)
{
WriteAstNode("inputExpression", expression.InputExpression);
}
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
_xmlWriter.WriteStartElement("whenThenPair");
_xmlWriter.WriteAttributeString("index", XmlConvert.ToString(i));
WriteAstNode("whenExpression", expression.WhenExpressions[i]);
WriteAstNode("thenExpression", expression.ThenExpressions[i]);
_xmlWriter.WriteEndElement();
}
if (expression.ElseExpression != null)
{
WriteAstNode("elseExpression", expression.ElseExpression);
}
_xmlWriter.WriteEndElement();
return(expression);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
if (expression.InputExpression == null)
{
_writer.Write("CASE");
}
else
{
_writer.Write("CASE ");
Visit(expression.InputExpression);
}
for (int i = 0; i < expression.WhenExpressions.Length && i < expression.ThenExpressions.Length; i++)
{
_writer.Write(" WHEN ");
Visit(expression.WhenExpressions[i]);
_writer.Write(" THEN ");
Visit(expression.ThenExpressions[i]);
}
if (expression.ElseExpression != null)
{
_writer.Write(" ELSE ");
Visit(expression.ElseExpression);
}
_writer.Write(" END");
return(expression);
}
public override AstElement Clone(Dictionary <AstElement, AstElement> alreadyClonedElements)
{
CaseExpression result = new CaseExpression();
if (_inputExpression != null)
{
result.InputExpression = (ExpressionNode)_inputExpression.Clone(alreadyClonedElements);
}
if (_elseExpression != null)
{
result.ElseExpression = (ExpressionNode)_elseExpression.Clone(alreadyClonedElements);
}
result.WhenExpressions = new ExpressionNode[_whenExpressions.Length];
for (int i = 0; i < _whenExpressions.Length; i++)
{
result.WhenExpressions[i] = (ExpressionNode)_whenExpressions[i].Clone(alreadyClonedElements);
}
result.ThenExpressions = new ExpressionNode[_thenExpressions.Length];
for (int i = 0; i < _thenExpressions.Length; i++)
{
result.ThenExpressions[i] = (ExpressionNode)_thenExpressions[i].Clone(alreadyClonedElements);
}
result.ResultType = _resultType;
return(result);
}
public override ExpressionNode VisitNullIfExpression(NullIfExpression expression)
{
// First visit all expressions
base.VisitNullIfExpression(expression);
// Since a NULLIF expression can be expressed using a CASE expression we convert
// them to simplify the evaluation and optimization engine.
//
// NULLIF(expression1, expression1) is equivalent to this CASE expression:
//
// CASE
// WHEN expression1 = expression2 THEN NULL
// ELSE expression1
// END
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[1];
caseExpression.ThenExpressions = new ExpressionNode[1];
caseExpression.WhenExpressions[0] = new BinaryExpression(BinaryOperator.Equal, expression.LeftExpression, expression.RightExpression);
caseExpression.ThenExpressions[0] = LiteralExpression.FromNull();
caseExpression.ElseExpression = expression.LeftExpression;
return(VisitExpression(caseExpression));
}
public override ExpressionNode VisitCoalesceExpression(CoalesceExpression expression)
{
// First visit all expressions
base.VisitCoalesceExpression(expression);
// Since a COALESCE expression can be expressed using a CASE expression we convert
// them to simplify the evaluation and optimization engine.
//
// COALESCE(expression1,...,expressionN) is equivalent to this CASE expression:
//
// CASE
// WHEN (expression1 IS NOT NULL) THEN expression1
// ...
// WHEN (expressionN IS NOT NULL) THEN expressionN
// END
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[expression.Expressions.Length];
caseExpression.ThenExpressions = new ExpressionNode[expression.Expressions.Length];
for (int i = 0; i < expression.Expressions.Length; i++)
{
ExpressionNode whenPart = expression.Expressions[i];
ExpressionNode thenPart = (ExpressionNode)whenPart.Clone();
caseExpression.WhenExpressions[i] = new IsNullExpression(true, whenPart);
caseExpression.ThenExpressions[i] = thenPart;
}
return(VisitExpression(caseExpression));
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// NOTE: It is assumed that simple case expressions are already transformed into
// searched case expressions, i.e.
// CASE
// WHEN Pred1 THEN Expr1 ...
// WHEN PredN THEN ExprN
// [ELSE ElseExpr]
// END
List <ExpressionNode> processedWhenExpressions = new List <ExpressionNode>();
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
SetWhenPassthru(processedWhenExpressions);
expression.WhenExpressions[i] = VisitExpression(expression.WhenExpressions[i]);
processedWhenExpressions.Add(expression.WhenExpressions[i]);
SetThenPassthru(processedWhenExpressions);
expression.ThenExpressions[i] = VisitExpression(expression.ThenExpressions[i]);
}
if (expression.ElseExpression != null)
{
SetWhenPassthru(processedWhenExpressions);
expression.ElseExpression = VisitExpression(expression.ElseExpression);
}
_currentPassthruPredicate = null;
return(expression);
}
private static bool VisitCaseExpression(CaseExpression node1, CaseExpression node2)
{
if (node2 == null)
{
return(false);
}
if (node1.InputExpression != null)
{
if (!Visit(node1.InputExpression, node2.InputExpression))
{
return(false);
}
}
if (node1.WhenExpressions.Length != node2.WhenExpressions.Length ||
node1.ThenExpressions.Length != node2.ThenExpressions.Length)
{
return(false);
}
for (int i = 0; i < node1.WhenExpressions.Length; i++)
{
if (!Visit(node1.WhenExpressions[i], node2.WhenExpressions[i]))
{
return(false);
}
}
for (int i = 0; i < node1.ThenExpressions.Length; i++)
{
if (!Visit(node1.ThenExpressions[i], node2.ThenExpressions[i]))
{
return(false);
}
}
if (node1.ElseExpression != null)
{
if (!Visit(node1.ElseExpression, node2.ElseExpression))
{
return(false);
}
}
return(true);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// NOTE: Must be searched CASE. The normalizer should have replaced it.
Label finishLabel = _ilEmitContext.ILGenerator.DefineLabel();
Label[] caseLabels = new Label[expression.WhenExpressions.Length + 1];
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
caseLabels[i] = _ilEmitContext.ILGenerator.DefineLabel();
}
Label elseLabel = _ilEmitContext.ILGenerator.DefineLabel();
caseLabels[expression.WhenExpressions.Length] = elseLabel;
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
_ilEmitContext.ILGenerator.MarkLabel(caseLabels[i]);
int whenLocalIndex = DeclareLocal();
Visit(expression.WhenExpressions[i]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Stloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Brfalse, caseLabels[i + 1]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Unbox_Any, typeof(bool));
_ilEmitContext.ILGenerator.Emit(OpCodes.Brfalse, caseLabels[i + 1]);
Visit(expression.ThenExpressions[i]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Br, finishLabel);
}
_ilEmitContext.ILGenerator.MarkLabel(elseLabel);
if (expression.ElseExpression != null)
{
Visit(expression.ElseExpression);
}
else
{
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldnull);
}
_ilEmitContext.ILGenerator.MarkLabel(finishLabel);
return(expression);
}
public override AstElement Clone(Dictionary<AstElement, AstElement> alreadyClonedElements)
{
CaseExpression result = new CaseExpression();
if (_inputExpression != null)
result.InputExpression = (ExpressionNode)_inputExpression.Clone(alreadyClonedElements);
if (_elseExpression != null)
result.ElseExpression = (ExpressionNode)_elseExpression.Clone(alreadyClonedElements);
result.WhenExpressions = new ExpressionNode[_whenExpressions.Length];
for (int i = 0; i < _whenExpressions.Length; i++)
result.WhenExpressions[i] = (ExpressionNode)_whenExpressions[i].Clone(alreadyClonedElements);
result.ThenExpressions = new ExpressionNode[_thenExpressions.Length];
for (int i = 0; i < _thenExpressions.Length; i++)
result.ThenExpressions[i] = (ExpressionNode)_thenExpressions[i].Clone(alreadyClonedElements);
result.ResultType = _resultType;
return result;
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// Replace simple CASE by searched CASE, i.e.
//
// replace
//
// CASE InputExpr
// WHEN Expr1 THEN ThenExpr1 ...
// WHEN ExprN THEN ThenExprN
// [ELSE ElseExpr]
// END
//
// by
//
// CASE
// WHEN InputExpr = Expr1 THEN ThenExpr1 ...
// WHEN InputExpr = ExprN THEN ThenExprN
// [ELSE ElseExpr]
// END
if (expression.InputExpression != null)
{
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
BinaryExpression binaryExpression = new BinaryExpression();
binaryExpression.Op = BinaryOperator.Equal;
binaryExpression.Left = (ExpressionNode)expression.InputExpression.Clone();
binaryExpression.Right = expression.WhenExpressions[i];
expression.WhenExpressions[i] = binaryExpression;
}
expression.InputExpression = null;
}
return(base.VisitCaseExpression(expression));
}
public virtual ExpressionNode VisitCaseExpression(CaseExpression expression)
{
if (expression.InputExpression != null)
{
expression.InputExpression = VisitExpression(expression.InputExpression);
}
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
expression.WhenExpressions[i] = VisitExpression(expression.WhenExpressions[i]);
}
for (int i = 0; i < expression.ThenExpressions.Length; i++)
{
expression.ThenExpressions[i] = VisitExpression(expression.ThenExpressions[i]);
}
if (expression.ElseExpression != null)
{
expression.ElseExpression = VisitExpression(expression.ElseExpression);
}
return(expression);
}
private static bool VisitCaseExpression(CaseExpression node1, CaseExpression node2)
{
if (node2 == null)
return false;
if (node1.InputExpression != null)
if (!Visit(node1.InputExpression, node2.InputExpression))
return false;
if (node1.WhenExpressions.Length != node2.WhenExpressions.Length ||
node1.ThenExpressions.Length != node2.ThenExpressions.Length)
return false;
for (int i = 0; i < node1.WhenExpressions.Length; i++)
if (!Visit(node1.WhenExpressions[i], node2.WhenExpressions[i]))
return false;
for (int i = 0; i < node1.ThenExpressions.Length; i++)
if (!Visit(node1.ThenExpressions[i], node2.ThenExpressions[i]))
return false;
if (node1.ElseExpression != null)
if (!Visit(node1.ElseExpression, node2.ElseExpression))
return false;
return true;
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// NOTE: It is assumed that simple case expressions are already transformed into
// searched case expressions, i.e.
// CASE
// WHEN Pred1 THEN Expr1 ...
// WHEN PredN THEN ExprN
// [ELSE ElseExpr]
// END
List<ExpressionNode> processedWhenExpressions = new List<ExpressionNode>();
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
SetWhenPassthru(processedWhenExpressions);
expression.WhenExpressions[i] = VisitExpression(expression.WhenExpressions[i]);
processedWhenExpressions.Add(expression.WhenExpressions[i]);
SetThenPassthru(processedWhenExpressions);
expression.ThenExpressions[i] = VisitExpression(expression.ThenExpressions[i]);
}
if (expression.ElseExpression != null)
{
SetWhenPassthru(processedWhenExpressions);
expression.ElseExpression = VisitExpression(expression.ElseExpression);
}
_currentPassthruPredicate = null;
return expression;
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
if (expression.InputExpression == null)
{
_writer.Write("CASE");
}
else
{
_writer.Write("CASE ");
Visit(expression.InputExpression);
}
for (int i = 0; i < expression.WhenExpressions.Length && i < expression.ThenExpressions.Length; i++)
{
_writer.Write(" WHEN ");
Visit(expression.WhenExpressions[i]);
_writer.Write(" THEN ");
Visit(expression.ThenExpressions[i]);
}
if (expression.ElseExpression != null)
{
_writer.Write(" ELSE ");
Visit(expression.ElseExpression);
}
_writer.Write(" END");
return expression;
}
private static AlgebraNode AlgebrizeRecursiveCte(CommonTableBinding commonTableBinding)
{
// It is a recursive query.
//
// Create row buffer entry that is used to guard the recursion and the primary table spool
// that spools the results needed by nested recursion calls.
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
StackedTableSpoolAlgebraNode primaryTableSpool = new StackedTableSpoolAlgebraNode();
RowBufferEntry anchorRecursionLevel;
RowBufferEntry[] anchorOutput;
AlgebraNode anchorNode;
#region Anchor member
{
// Emit anchor member.
AlgebraNode algebrizedAnchor = Convert(commonTableBinding.AnchorMember);
// Emit compute scalar that initializes the recursion level to 0.
anchorRecursionLevel = new RowBufferEntry(typeof(int));
ComputedValueDefinition computedValueDefinition1 = new ComputedValueDefinition();
computedValueDefinition1.Target = anchorRecursionLevel;
computedValueDefinition1.Expression = LiteralExpression.FromInt32(0);
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = algebrizedAnchor;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { computedValueDefinition1 };
anchorOutput = algebrizedAnchor.OutputList;
anchorNode = computeScalarAlgebraNode;
}
#endregion
RowBufferEntry incrementedRecursionLevel;
RowBufferEntry[] tableSpoolOutput;
AlgebraNode tableSpoolNode;
#region Table spool
{
// Emit table spool reference.
RowBufferEntry recursionLevelRefEntry = new RowBufferEntry(typeof(int));
tableSpoolOutput = new RowBufferEntry[anchorOutput.Length];
for (int i = 0; i < tableSpoolOutput.Length; i++)
tableSpoolOutput[i] = new RowBufferEntry(anchorOutput[i].DataType);
StackedTableSpoolRefAlgebraNode tableSpoolReference = new StackedTableSpoolRefAlgebraNode();
tableSpoolReference.PrimarySpool = primaryTableSpool;
tableSpoolReference.DefinedValues = ArrayHelpers.JoinArrays(new RowBufferEntry[] { recursionLevelRefEntry }, tableSpoolOutput);
// Emit compute scalar that increases the recursion level by one and renames
// columns from the spool to the CTE column buffer entries.
expressionBuilder.Push(new RowBufferEntryExpression(recursionLevelRefEntry));
expressionBuilder.Push(LiteralExpression.FromInt32(1));
expressionBuilder.PushBinary(BinaryOperator.Add);
incrementedRecursionLevel = new RowBufferEntry(typeof(int));
ComputedValueDefinition incremenedRecLevelValueDefinition = new ComputedValueDefinition();
incremenedRecLevelValueDefinition.Target = incrementedRecursionLevel;
incremenedRecLevelValueDefinition.Expression = expressionBuilder.Pop();
CteColumnMappingFinder cteColumnMappingFinder = new CteColumnMappingFinder(commonTableBinding, tableSpoolOutput);
foreach (QueryNode recursiveMember in commonTableBinding.RecursiveMembers)
cteColumnMappingFinder.Visit(recursiveMember);
CteColumnMapping[] cteColumnMappings = cteColumnMappingFinder.GetMappings();
List<ComputedValueDefinition> definedValues = new List<ComputedValueDefinition>();
definedValues.Add(incremenedRecLevelValueDefinition);
foreach (CteColumnMapping cteColumnMapping in cteColumnMappings)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = cteColumnMapping.VirtualBufferEntry;
definedValue.Expression = new RowBufferEntryExpression(cteColumnMapping.SpoolBufferEntry);
definedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = tableSpoolReference;
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
tableSpoolNode = computeScalarAlgebraNode;
}
#endregion
RowBufferEntry[] recursiveOutput;
AlgebraNode recursiveNode;
#region Recursive member(s)
{
// Emit all recursive parts. The join conditions to the recursive part are replaced by simple filters
// in the nested Convert() call.
ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode();
concatAlgebraNode.Inputs = new AlgebraNode[commonTableBinding.RecursiveMembers.Length];
for (int i = 0; i < commonTableBinding.RecursiveMembers.Length; i++)
concatAlgebraNode.Inputs[i] = Convert(commonTableBinding, commonTableBinding.RecursiveMembers[i]);
concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length];
for (int i = 0; i < anchorOutput.Length; i++)
{
List<RowBufferEntry> dependencies = new List<RowBufferEntry>();
foreach (ResultAlgebraNode algebrizedRecursivePart in concatAlgebraNode.Inputs)
dependencies.Add(algebrizedRecursivePart.OutputList[i]);
concatAlgebraNode.DefinedValues[i] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[i].Target = new RowBufferEntry(anchorOutput[i].DataType);
concatAlgebraNode.DefinedValues[i].DependendEntries = dependencies.ToArray();
}
// Calculate the recursive output.
recursiveOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length];
for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++)
recursiveOutput[i] = concatAlgebraNode.DefinedValues[i].Target;
// Emit cross join
JoinAlgebraNode crossJoinNode = new JoinAlgebraNode();
crossJoinNode.Left = tableSpoolNode;
crossJoinNode.Right = concatAlgebraNode;
// Emit assert that ensures that the recursion level is <= 100.
expressionBuilder.Push(new RowBufferEntryExpression(incrementedRecursionLevel));
expressionBuilder.Push(LiteralExpression.FromInt32(100));
expressionBuilder.PushBinary(BinaryOperator.Greater);
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[1];
caseExpression.WhenExpressions[0] = expressionBuilder.Pop();
caseExpression.ThenExpressions = new ExpressionNode[1];
caseExpression.ThenExpressions[0] = LiteralExpression.FromInt32(0);
AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode();
assertAlgebraNode.Input = crossJoinNode;
assertAlgebraNode.AssertionType = AssertionType.BelowRecursionLimit;
assertAlgebraNode.Predicate = caseExpression;
recursiveNode = assertAlgebraNode;
}
#endregion
RowBufferEntry[] algebrizedOutput;
AlgebraNode algebrizedCte;
#region Combination
{
// Create concat node to combine anchor and recursive part.
ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode();
concatAlgebraNode.Inputs = new AlgebraNode[2];
concatAlgebraNode.Inputs[0] = anchorNode;
concatAlgebraNode.Inputs[1] = recursiveNode;
concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length + 1];
concatAlgebraNode.DefinedValues[0] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[0].Target = new RowBufferEntry(anchorRecursionLevel.DataType);
concatAlgebraNode.DefinedValues[0].DependendEntries = new RowBufferEntry[] { anchorRecursionLevel, incrementedRecursionLevel };
for (int i = 0; i < anchorOutput.Length; i++)
{
concatAlgebraNode.DefinedValues[i + 1] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[i + 1].Target = new RowBufferEntry(anchorOutput[i].DataType);
concatAlgebraNode.DefinedValues[i + 1].DependendEntries = new RowBufferEntry[] { anchorOutput[i], recursiveOutput[i] };
}
algebrizedOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length];
for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++)
algebrizedOutput[i] = concatAlgebraNode.DefinedValues[i].Target;
// Assign the combination as the input to the primray spool
primaryTableSpool.Input = concatAlgebraNode;
// The primary spool represents the result of the "inlined" CTE.
algebrizedCte = primaryTableSpool;
}
#endregion
algebrizedCte.OutputList = algebrizedOutput;
return algebrizedCte;
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
base.VisitCaseExpression(expression);
// NOTE: It must be a searched CASE. The normalizer should have normalized it already.
//
// Remove all WHEN expressions that are allays FALSE or NULL.
// AND
// Cut off all WHENs trailing an expression that is always true.
List<ExpressionNode> whenExpressions = new List<ExpressionNode>();
List<ExpressionNode> thenExpressions = new List<ExpressionNode>();
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
if (AstUtil.IsNull(expression.WhenExpressions[i]))
{
// A WHEN expression is always null.
continue;
}
ConstantExpression whenAsBooleanConstant = expression.WhenExpressions[i] as ConstantExpression;
if (whenAsBooleanConstant != null)
{
if (!whenAsBooleanConstant.AsBoolean)
{
// A WHEN expression is always false.
//
// We remove this part from the case expression by not adding to
// whenExpressions and thenExpressions.
continue;
}
else
{
// A WHEN expression is always true.
//
// We replace the ELSE expression by the THEN expression and
// cut off the rest.
expression.ElseExpression = expression.ThenExpressions[i];
break;
}
}
whenExpressions.Add(expression.WhenExpressions[i]);
thenExpressions.Add(expression.ThenExpressions[i]);
}
if (whenExpressions.Count == 0)
{
// This means the first WHEN expression was always false
// or all WHEN expressions are either FALSE or NULL.
//
// We replace the case expression by the else expression
// or by NULL.
if (expression.ElseExpression != null)
return expression.ElseExpression;
return LiteralExpression.FromTypedNull(expression.ExpressionType);
}
expression.WhenExpressions = whenExpressions.ToArray();
expression.ThenExpressions = thenExpressions.ToArray();
return expression;
}
private ExpressionNode ParsePrimaryExpression()
{
switch (_token.Id)
{
case TokenId.NULL:
NextToken();
return LiteralExpression.FromNull();
case TokenId.TRUE:
case TokenId.FALSE:
return ParseBooleanLiteral();
case TokenId.Date:
return ParseDateLiteral();
case TokenId.Number:
return ParseNumberLiteral();
case TokenId.String:
return LiteralExpression.FromString(ParseString());
case TokenId.EXISTS:
{
ExistsSubselect result = new ExistsSubselect();
NextToken();
Match(TokenId.LeftParentheses);
result.Query = ParseQuery();
Match(TokenId.RightParentheses);
return result;
}
case TokenId.ParameterMarker:
{
_rangeRecorder.Begin();
NextToken();
Identifier name = ParseIdentifier();
SourceRange nameSourceRange = _rangeRecorder.End();
ParameterExpression result = new ParameterExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
return result;
}
case TokenId.CAST:
{
NextToken();
CastExpression castExpression = new CastExpression();
Match(TokenId.LeftParentheses);
castExpression.Expression = ParseExpression();
Match(TokenId.AS);
castExpression.TypeReference = ParseTypeReference();
Match(TokenId.RightParentheses);
return castExpression;
}
case TokenId.CASE:
{
NextToken();
CaseExpression caseExpression = new CaseExpression();
if (_token.Id != TokenId.WHEN && _token.Id != TokenId.ELSE && _token.Id != TokenId.END)
caseExpression.InputExpression = ParseExpression();
List<ExpressionNode> whenExpressionList = new List<ExpressionNode>();
List<ExpressionNode> expressionList = new List<ExpressionNode>();
if (_token.Id != TokenId.WHEN)
{
Match(TokenId.WHEN);
}
else
{
while (_token.Id == TokenId.WHEN)
{
NextToken();
whenExpressionList.Add(ParseExpression());
Match(TokenId.THEN);
expressionList.Add(ParseExpression());
}
}
caseExpression.WhenExpressions = whenExpressionList.ToArray();
caseExpression.ThenExpressions = expressionList.ToArray();
if (_token.Id == TokenId.ELSE)
{
NextToken();
caseExpression.ElseExpression = ParseExpression();
}
Match(TokenId.END);
return caseExpression;
}
case TokenId.COALESCE:
{
NextToken();
CoalesceExpression coalesceExpression = new CoalesceExpression();
coalesceExpression.Expressions = ParseExpressionList();
return coalesceExpression;
}
case TokenId.NULLIF:
{
NextToken();
NullIfExpression nullIfExpression = new NullIfExpression();
Match(TokenId.LeftParentheses);
nullIfExpression.LeftExpression = ParseExpression();
Match(TokenId.Comma);
nullIfExpression.RightExpression = ParseExpression();
Match(TokenId.RightParentheses);
return nullIfExpression;
}
case TokenId.Identifier:
{
_rangeRecorder.Begin();
Identifier name = ParseIdentifier();
SourceRange nameSourceRange = _rangeRecorder.End();
if (_token.Id != TokenId.LeftParentheses)
{
NameExpression result = new NameExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
return result;
}
else
{
bool hasAsteriskModifier;
ExpressionNode[] args;
if (_lookahead.Id != TokenId.Multiply)
{
hasAsteriskModifier = false;
args = ParseExpressionList();
}
else
{
NextToken();
NextToken();
Match(TokenId.RightParentheses);
hasAsteriskModifier = true;
args = new ExpressionNode[0];
}
FunctionInvocationExpression result = new FunctionInvocationExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
result.Arguments = args;
result.HasAsteriskModifier = hasAsteriskModifier;
return result;
}
}
case TokenId.LeftParentheses:
{
NextToken();
ExpressionNode expr;
if (_token.Id != TokenId.SELECT)
{
expr = ParseExpression();
}
else
{
SingleRowSubselect singleRowSubselect = new SingleRowSubselect();
singleRowSubselect.Query = ParseQuery();
expr = singleRowSubselect;
}
Match(TokenId.RightParentheses);
return expr;
}
default:
{
_errorReporter.SimpleExpressionExpected(_token.Range, _token.Text);
return LiteralExpression.FromNull();
}
}
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// Replace simple CASE by searched CASE, i.e.
//
// replace
//
// CASE InputExpr
// WHEN Expr1 THEN ThenExpr1 ...
// WHEN ExprN THEN ThenExprN
// [ELSE ElseExpr]
// END
//
// by
//
// CASE
// WHEN InputExpr = Expr1 THEN ThenExpr1 ...
// WHEN InputExpr = ExprN THEN ThenExprN
// [ELSE ElseExpr]
// END
if (expression.InputExpression != null)
{
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
BinaryExpression binaryExpression = new BinaryExpression();
binaryExpression.Op = BinaryOperator.Equal;
binaryExpression.Left = (ExpressionNode) expression.InputExpression.Clone();
binaryExpression.Right = expression.WhenExpressions[i];
expression.WhenExpressions[i] = binaryExpression;
}
expression.InputExpression = null;
}
return base.VisitCaseExpression(expression);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// NOTE: Must be searched CASE. The normalizer should have replaced it.
Label finishLabel = _ilEmitContext.ILGenerator.DefineLabel();
Label[] caseLabels = new Label[expression.WhenExpressions.Length + 1];
for (int i = 0; i < expression.WhenExpressions.Length; i++)
caseLabels[i] = _ilEmitContext.ILGenerator.DefineLabel();
Label elseLabel = _ilEmitContext.ILGenerator.DefineLabel();
caseLabels[expression.WhenExpressions.Length] = elseLabel;
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
_ilEmitContext.ILGenerator.MarkLabel(caseLabels[i]);
int whenLocalIndex = DeclareLocal();
Visit(expression.WhenExpressions[i]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Stloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Brfalse, caseLabels[i + 1]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldloc, whenLocalIndex);
_ilEmitContext.ILGenerator.Emit(OpCodes.Unbox_Any, typeof (bool));
_ilEmitContext.ILGenerator.Emit(OpCodes.Brfalse, caseLabels[i + 1]);
Visit(expression.ThenExpressions[i]);
_ilEmitContext.ILGenerator.Emit(OpCodes.Br, finishLabel);
}
_ilEmitContext.ILGenerator.MarkLabel(elseLabel);
if (expression.ElseExpression != null)
Visit(expression.ElseExpression);
else
_ilEmitContext.ILGenerator.Emit(OpCodes.Ldnull);
_ilEmitContext.ILGenerator.MarkLabel(finishLabel);
return expression;
}
public override ExpressionNode VisitCoalesceExpression(CoalesceExpression expression)
{
// First visit all expressions
base.VisitCoalesceExpression(expression);
// Since a COALESCE expression can be expressed using a CASE expression we convert
// them to simplify the evaluation and optimization engine.
//
// COALESCE(expression1,...,expressionN) is equivalent to this CASE expression:
//
// CASE
// WHEN (expression1 IS NOT NULL) THEN expression1
// ...
// WHEN (expressionN IS NOT NULL) THEN expressionN
// END
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[expression.Expressions.Length];
caseExpression.ThenExpressions = new ExpressionNode[expression.Expressions.Length];
for (int i = 0; i < expression.Expressions.Length; i++)
{
ExpressionNode whenPart = expression.Expressions[i];
ExpressionNode thenPart = (ExpressionNode) whenPart.Clone();
caseExpression.WhenExpressions[i] = new IsNullExpression(true, whenPart);
caseExpression.ThenExpressions[i] = thenPart;
}
return VisitExpression(caseExpression);
}
public override ExpressionNode VisitNullIfExpression(NullIfExpression expression)
{
// First visit all expressions
base.VisitNullIfExpression (expression);
// Since a NULLIF expression can be expressed using a CASE expression we convert
// them to simplify the evaluation and optimization engine.
//
// NULLIF(expression1, expression1) is equivalent to this CASE expression:
//
// CASE
// WHEN expression1 = expression2 THEN NULL
// ELSE expression1
// END
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[1];
caseExpression.ThenExpressions = new ExpressionNode[1];
caseExpression.WhenExpressions[0] = new BinaryExpression(BinaryOperator.Equal, expression.LeftExpression, expression.RightExpression);
caseExpression.ThenExpressions[0] = LiteralExpression.FromNull();
caseExpression.ElseExpression = expression.LeftExpression;
return VisitExpression(caseExpression);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
_xmlWriter.WriteStartElement("caseExpression");
WriteTypeAttribute(expression.ExpressionType);
if (expression.InputExpression != null)
WriteAstNode("inputExpression", expression.InputExpression);
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
_xmlWriter.WriteStartElement("whenThenPair");
_xmlWriter.WriteAttributeString("index", XmlConvert.ToString(i));
WriteAstNode("whenExpression", expression.WhenExpressions[i]);
WriteAstNode("thenExpression", expression.ThenExpressions[i]);
_xmlWriter.WriteEndElement();
}
if (expression.ElseExpression != null)
WriteAstNode("elseExpression", expression.ElseExpression);
_xmlWriter.WriteEndElement();
return expression;
}
private static ResultAlgebraNode CreateAssertedSubquery(ResultAlgebraNode inputNode)
{
if (AstUtil.WillProduceAtMostOneRow(inputNode))
{
return(inputNode);
}
RowBufferEntry inputEntry = inputNode.OutputList[0];
AggregatedValueDefinition countDefinedValue = new AggregatedValueDefinition();
countDefinedValue.Aggregate = new CountAggregateBinding("COUNT");
countDefinedValue.Aggregator = countDefinedValue.Aggregate.CreateAggregator(typeof(int));
countDefinedValue.Argument = LiteralExpression.FromInt32(0);
RowBufferEntry countDefinedValueEntry = new RowBufferEntry(countDefinedValue.Aggregator.ReturnType);
countDefinedValue.Target = countDefinedValueEntry;
RowBufferEntryExpression anyAggregateArgument = new RowBufferEntryExpression();
anyAggregateArgument.RowBufferEntry = inputEntry;
AggregatedValueDefinition anyDefinedValue = new AggregatedValueDefinition();
anyDefinedValue.Aggregate = new FirstAggregateBinding("ANY");
anyDefinedValue.Aggregator = anyDefinedValue.Aggregate.CreateAggregator(inputEntry.DataType);
anyDefinedValue.Argument = anyAggregateArgument;
RowBufferEntry anyDefinedValueEntry = new RowBufferEntry(inputEntry.DataType);
anyDefinedValue.Target = anyDefinedValueEntry;
AggregateAlgebraNode aggregateAlgebraNode = new AggregateAlgebraNode();
aggregateAlgebraNode.Input = inputNode.Input;
aggregateAlgebraNode.DefinedValues = new AggregatedValueDefinition[] { countDefinedValue, anyDefinedValue };
// CASE WHEN SubqueryCount > 1 THEN 0 ELSE NULL END
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(new RowBufferEntryExpression(countDefinedValueEntry));
expressionBuilder.Push(LiteralExpression.FromInt32(1));
expressionBuilder.PushBinary(BinaryOperator.Greater);
ExpressionNode whenExpression = expressionBuilder.Pop();
ExpressionNode thenExpression = LiteralExpression.FromInt32(0);
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[] { whenExpression };
caseExpression.ThenExpressions = new ExpressionNode[] { thenExpression };
expressionBuilder.Push(caseExpression);
ExpressionNode predicate = expressionBuilder.Pop();
AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode();
assertAlgebraNode.Input = aggregateAlgebraNode;
assertAlgebraNode.Predicate = predicate;
assertAlgebraNode.AssertionType = AssertionType.MaxOneRow;
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = assertAlgebraNode;
resultAlgebraNode.OutputList = new RowBufferEntry[] { anyDefinedValueEntry };
resultAlgebraNode.ColumnNames = inputNode.ColumnNames;
return(resultAlgebraNode);
}
private static ResultAlgebraNode CreateAssertedSubquery(ResultAlgebraNode inputNode)
{
if (AstUtil.WillProduceAtMostOneRow(inputNode))
return inputNode;
RowBufferEntry inputEntry = inputNode.OutputList[0];
AggregatedValueDefinition countDefinedValue = new AggregatedValueDefinition();
countDefinedValue.Aggregate = new CountAggregateBinding("COUNT");
countDefinedValue.Aggregator = countDefinedValue.Aggregate.CreateAggregator(typeof(int));
countDefinedValue.Argument = LiteralExpression.FromInt32(0);
RowBufferEntry countDefinedValueEntry = new RowBufferEntry(countDefinedValue.Aggregator.ReturnType);
countDefinedValue.Target = countDefinedValueEntry;
RowBufferEntryExpression anyAggregateArgument = new RowBufferEntryExpression();
anyAggregateArgument.RowBufferEntry = inputEntry;
AggregatedValueDefinition anyDefinedValue = new AggregatedValueDefinition();
anyDefinedValue.Aggregate = new FirstAggregateBinding("ANY");
anyDefinedValue.Aggregator = anyDefinedValue.Aggregate.CreateAggregator(inputEntry.DataType);
anyDefinedValue.Argument = anyAggregateArgument;
RowBufferEntry anyDefinedValueEntry = new RowBufferEntry(inputEntry.DataType);
anyDefinedValue.Target = anyDefinedValueEntry;
AggregateAlgebraNode aggregateAlgebraNode = new AggregateAlgebraNode();
aggregateAlgebraNode.Input = inputNode.Input;
aggregateAlgebraNode.DefinedValues = new AggregatedValueDefinition[] { countDefinedValue, anyDefinedValue };
// CASE WHEN SubqueryCount > 1 THEN 0 ELSE NULL END
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
expressionBuilder.Push(new RowBufferEntryExpression(countDefinedValueEntry));
expressionBuilder.Push(LiteralExpression.FromInt32(1));
expressionBuilder.PushBinary(BinaryOperator.Greater);
ExpressionNode whenExpression = expressionBuilder.Pop();
ExpressionNode thenExpression = LiteralExpression.FromInt32(0);
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[] { whenExpression };
caseExpression.ThenExpressions = new ExpressionNode[] { thenExpression };
expressionBuilder.Push(caseExpression);
ExpressionNode predicate = expressionBuilder.Pop();
AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode();
assertAlgebraNode.Input = aggregateAlgebraNode;
assertAlgebraNode.Predicate = predicate;
assertAlgebraNode.AssertionType = AssertionType.MaxOneRow;
ResultAlgebraNode resultAlgebraNode = new ResultAlgebraNode();
resultAlgebraNode.Input = assertAlgebraNode;
resultAlgebraNode.OutputList = new RowBufferEntry[] { anyDefinedValueEntry };
resultAlgebraNode.ColumnNames = inputNode.ColumnNames;
return resultAlgebraNode;
}
public virtual ExpressionNode VisitCaseExpression(CaseExpression expression)
{
if (expression.InputExpression != null)
expression.InputExpression = VisitExpression(expression.InputExpression);
for (int i = 0; i < expression.WhenExpressions.Length; i++)
expression.WhenExpressions[i] = VisitExpression(expression.WhenExpressions[i]);
for (int i = 0; i < expression.ThenExpressions.Length; i++)
expression.ThenExpressions[i] = VisitExpression(expression.ThenExpressions[i]);
if (expression.ElseExpression != null)
expression.ElseExpression = VisitExpression(expression.ElseExpression);
return expression;
}
private ExpressionNode ParsePrimaryExpression()
{
switch (_token.Id)
{
case TokenId.NULL:
NextToken();
return(LiteralExpression.FromNull());
case TokenId.TRUE:
case TokenId.FALSE:
return(ParseBooleanLiteral());
case TokenId.Date:
return(ParseDateLiteral());
case TokenId.Number:
return(ParseNumberLiteral());
case TokenId.String:
return(LiteralExpression.FromString(ParseString()));
case TokenId.EXISTS:
{
ExistsSubselect result = new ExistsSubselect();
NextToken();
Match(TokenId.LeftParentheses);
result.Query = ParseQuery();
Match(TokenId.RightParentheses);
return(result);
}
case TokenId.ParameterMarker:
{
_rangeRecorder.Begin();
NextToken();
Identifier name = ParseIdentifier();
SourceRange nameSourceRange = _rangeRecorder.End();
ParameterExpression result = new ParameterExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
return(result);
}
case TokenId.CAST:
{
NextToken();
CastExpression castExpression = new CastExpression();
Match(TokenId.LeftParentheses);
castExpression.Expression = ParseExpression();
Match(TokenId.AS);
castExpression.TypeReference = ParseTypeReference();
Match(TokenId.RightParentheses);
return(castExpression);
}
case TokenId.CASE:
{
NextToken();
CaseExpression caseExpression = new CaseExpression();
if (_token.Id != TokenId.WHEN && _token.Id != TokenId.ELSE && _token.Id != TokenId.END)
{
caseExpression.InputExpression = ParseExpression();
}
List <ExpressionNode> whenExpressionList = new List <ExpressionNode>();
List <ExpressionNode> expressionList = new List <ExpressionNode>();
if (_token.Id != TokenId.WHEN)
{
Match(TokenId.WHEN);
}
else
{
while (_token.Id == TokenId.WHEN)
{
NextToken();
whenExpressionList.Add(ParseExpression());
Match(TokenId.THEN);
expressionList.Add(ParseExpression());
}
}
caseExpression.WhenExpressions = whenExpressionList.ToArray();
caseExpression.ThenExpressions = expressionList.ToArray();
if (_token.Id == TokenId.ELSE)
{
NextToken();
caseExpression.ElseExpression = ParseExpression();
}
Match(TokenId.END);
return(caseExpression);
}
case TokenId.COALESCE:
{
NextToken();
CoalesceExpression coalesceExpression = new CoalesceExpression();
coalesceExpression.Expressions = ParseExpressionList();
return(coalesceExpression);
}
case TokenId.NULLIF:
{
NextToken();
NullIfExpression nullIfExpression = new NullIfExpression();
Match(TokenId.LeftParentheses);
nullIfExpression.LeftExpression = ParseExpression();
Match(TokenId.Comma);
nullIfExpression.RightExpression = ParseExpression();
Match(TokenId.RightParentheses);
return(nullIfExpression);
}
case TokenId.Identifier:
{
_rangeRecorder.Begin();
Identifier name = ParseIdentifier();
SourceRange nameSourceRange = _rangeRecorder.End();
if (_token.Id != TokenId.LeftParentheses)
{
NameExpression result = new NameExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
return(result);
}
else
{
bool hasAsteriskModifier;
ExpressionNode[] args;
if (_lookahead.Id != TokenId.Multiply)
{
hasAsteriskModifier = false;
args = ParseExpressionList();
}
else
{
NextToken();
NextToken();
Match(TokenId.RightParentheses);
hasAsteriskModifier = true;
args = new ExpressionNode[0];
}
FunctionInvocationExpression result = new FunctionInvocationExpression();
result.Name = name;
result.NameSourceRange = nameSourceRange;
result.Arguments = args;
result.HasAsteriskModifier = hasAsteriskModifier;
return(result);
}
}
case TokenId.LeftParentheses:
{
NextToken();
ExpressionNode expr;
if (_token.Id != TokenId.SELECT)
{
expr = ParseExpression();
}
else
{
SingleRowSubselect singleRowSubselect = new SingleRowSubselect();
singleRowSubselect.Query = ParseQuery();
expr = singleRowSubselect;
}
Match(TokenId.RightParentheses);
return(expr);
}
default:
{
_errorReporter.SimpleExpressionExpected(_token.Range, _token.Text);
return(LiteralExpression.FromNull());
}
}
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
base.VisitCaseExpression(expression);
// NOTE: It must be a searched CASE. The normalizer should have normalized it already.
//
// Remove all WHEN expressions that are allays FALSE or NULL.
// AND
// Cut off all WHENs trailing an expression that is always true.
List <ExpressionNode> whenExpressions = new List <ExpressionNode>();
List <ExpressionNode> thenExpressions = new List <ExpressionNode>();
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
if (AstUtil.IsNull(expression.WhenExpressions[i]))
{
// A WHEN expression is always null.
continue;
}
ConstantExpression whenAsBooleanConstant = expression.WhenExpressions[i] as ConstantExpression;
if (whenAsBooleanConstant != null)
{
if (!whenAsBooleanConstant.AsBoolean)
{
// A WHEN expression is always false.
//
// We remove this part from the case expression by not adding to
// whenExpressions and thenExpressions.
continue;
}
else
{
// A WHEN expression is always true.
//
// We replace the ELSE expression by the THEN expression and
// cut off the rest.
expression.ElseExpression = expression.ThenExpressions[i];
break;
}
}
whenExpressions.Add(expression.WhenExpressions[i]);
thenExpressions.Add(expression.ThenExpressions[i]);
}
if (whenExpressions.Count == 0)
{
// This means the first WHEN expression was always false
// or all WHEN expressions are either FALSE or NULL.
//
// We replace the case expression by the else expression
// or by NULL.
if (expression.ElseExpression != null)
{
return(expression.ElseExpression);
}
return(LiteralExpression.FromTypedNull(expression.ExpressionType));
}
expression.WhenExpressions = whenExpressions.ToArray();
expression.ThenExpressions = thenExpressions.ToArray();
return(expression);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// Ensure all nested expressions are fully resolved.
base.VisitCaseExpression(expression);
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
if (expression.WhenExpressions[i].ExpressionType == null || expression.ThenExpressions[i].ExpressionType == null)
return expression;
}
if (expression.ElseExpression != null && expression.ElseExpression.ExpressionType == null)
return expression;
// Ok, all nested expressions could be fully resolved. Lets validate the CASE expression.
// The semantic of CASE says that if no expression incl. ELSE does match the result is NULL.
// So having an ELSE expression that returns NULL is quite redundant.
LiteralExpression elseAsLiteral = expression.ElseExpression as LiteralExpression;
if (elseAsLiteral != null && elseAsLiteral.IsNullValue)
expression.ElseExpression = null;
// All WHEN expressions must evaluate to bool.
foreach (ExpressionNode whenExpression in expression.WhenExpressions)
{
if (whenExpression.ExpressionType != typeof(bool) && whenExpression.ExpressionType != typeof(DBNull))
_errorReporter.WhenMustEvaluateToBoolIfCaseInputIsOmitted(whenExpression);
}
// Check that all result expression incl. else share a common type.
//
// To do this and to support good error reporting we first try to find
// the best common type. Any needed conversions or type errors are
// ignored.
Type commonResultType = expression.ThenExpressions[0].ExpressionType;
for (int i = 1; i < expression.ThenExpressions.Length; i++)
{
commonResultType = _binder.ChooseBetterTypeConversion(commonResultType, expression.ThenExpressions[i].ExpressionType);
}
if (expression.ElseExpression != null)
commonResultType = _binder.ChooseBetterTypeConversion(expression.ElseExpression.ExpressionType, commonResultType);
// Now we know that commonResultType is the best type for all result expressions.
// Insert cast nodes for all expressions that have a different type but are
// implicit convertible and report errors for all expressions that not convertible.
if (expression.ElseExpression != null)
{
expression.ElseExpression = _binder.ConvertExpressionIfRequired(expression.ElseExpression, commonResultType);
}
for (int i = 0; i < expression.ThenExpressions.Length; i++)
{
expression.ThenExpressions[i] = _binder.ConvertExpressionIfRequired(expression.ThenExpressions[i], commonResultType);
}
expression.ResultType = commonResultType;
return expression;
}
private static AlgebraNode AlgebrizeRecursiveCte(CommonTableBinding commonTableBinding)
{
// It is a recursive query.
//
// Create row buffer entry that is used to guard the recursion and the primary table spool
// that spools the results needed by nested recursion calls.
ExpressionBuilder expressionBuilder = new ExpressionBuilder();
StackedTableSpoolAlgebraNode primaryTableSpool = new StackedTableSpoolAlgebraNode();
RowBufferEntry anchorRecursionLevel;
RowBufferEntry[] anchorOutput;
AlgebraNode anchorNode;
#region Anchor member
{
// Emit anchor member.
AlgebraNode algebrizedAnchor = Convert(commonTableBinding.AnchorMember);
// Emit compute scalar that initializes the recursion level to 0.
anchorRecursionLevel = new RowBufferEntry(typeof(int));
ComputedValueDefinition computedValueDefinition1 = new ComputedValueDefinition();
computedValueDefinition1.Target = anchorRecursionLevel;
computedValueDefinition1.Expression = LiteralExpression.FromInt32(0);
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = algebrizedAnchor;
computeScalarAlgebraNode.DefinedValues = new ComputedValueDefinition[] { computedValueDefinition1 };
anchorOutput = algebrizedAnchor.OutputList;
anchorNode = computeScalarAlgebraNode;
}
#endregion
RowBufferEntry incrementedRecursionLevel;
RowBufferEntry[] tableSpoolOutput;
AlgebraNode tableSpoolNode;
#region Table spool
{
// Emit table spool reference.
RowBufferEntry recursionLevelRefEntry = new RowBufferEntry(typeof(int));
tableSpoolOutput = new RowBufferEntry[anchorOutput.Length];
for (int i = 0; i < tableSpoolOutput.Length; i++)
{
tableSpoolOutput[i] = new RowBufferEntry(anchorOutput[i].DataType);
}
StackedTableSpoolRefAlgebraNode tableSpoolReference = new StackedTableSpoolRefAlgebraNode();
tableSpoolReference.PrimarySpool = primaryTableSpool;
tableSpoolReference.DefinedValues = ArrayHelpers.JoinArrays(new RowBufferEntry[] { recursionLevelRefEntry }, tableSpoolOutput);
// Emit compute scalar that increases the recursion level by one and renames
// columns from the spool to the CTE column buffer entries.
expressionBuilder.Push(new RowBufferEntryExpression(recursionLevelRefEntry));
expressionBuilder.Push(LiteralExpression.FromInt32(1));
expressionBuilder.PushBinary(BinaryOperator.Add);
incrementedRecursionLevel = new RowBufferEntry(typeof(int));
ComputedValueDefinition incremenedRecLevelValueDefinition = new ComputedValueDefinition();
incremenedRecLevelValueDefinition.Target = incrementedRecursionLevel;
incremenedRecLevelValueDefinition.Expression = expressionBuilder.Pop();
CteColumnMappingFinder cteColumnMappingFinder = new CteColumnMappingFinder(commonTableBinding, tableSpoolOutput);
foreach (QueryNode recursiveMember in commonTableBinding.RecursiveMembers)
{
cteColumnMappingFinder.Visit(recursiveMember);
}
CteColumnMapping[] cteColumnMappings = cteColumnMappingFinder.GetMappings();
List <ComputedValueDefinition> definedValues = new List <ComputedValueDefinition>();
definedValues.Add(incremenedRecLevelValueDefinition);
foreach (CteColumnMapping cteColumnMapping in cteColumnMappings)
{
ComputedValueDefinition definedValue = new ComputedValueDefinition();
definedValue.Target = cteColumnMapping.VirtualBufferEntry;
definedValue.Expression = new RowBufferEntryExpression(cteColumnMapping.SpoolBufferEntry);
definedValues.Add(definedValue);
}
ComputeScalarAlgebraNode computeScalarAlgebraNode = new ComputeScalarAlgebraNode();
computeScalarAlgebraNode.Input = tableSpoolReference;
computeScalarAlgebraNode.DefinedValues = definedValues.ToArray();
tableSpoolNode = computeScalarAlgebraNode;
}
#endregion
RowBufferEntry[] recursiveOutput;
AlgebraNode recursiveNode;
#region Recursive member(s)
{
// Emit all recursive parts. The join conditions to the recursive part are replaced by simple filters
// in the nested Convert() call.
ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode();
concatAlgebraNode.Inputs = new AlgebraNode[commonTableBinding.RecursiveMembers.Length];
for (int i = 0; i < commonTableBinding.RecursiveMembers.Length; i++)
{
concatAlgebraNode.Inputs[i] = Convert(commonTableBinding, commonTableBinding.RecursiveMembers[i]);
}
concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length];
for (int i = 0; i < anchorOutput.Length; i++)
{
List <RowBufferEntry> dependencies = new List <RowBufferEntry>();
foreach (ResultAlgebraNode algebrizedRecursivePart in concatAlgebraNode.Inputs)
{
dependencies.Add(algebrizedRecursivePart.OutputList[i]);
}
concatAlgebraNode.DefinedValues[i] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[i].Target = new RowBufferEntry(anchorOutput[i].DataType);
concatAlgebraNode.DefinedValues[i].DependendEntries = dependencies.ToArray();
}
// Calculate the recursive output.
recursiveOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length];
for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++)
{
recursiveOutput[i] = concatAlgebraNode.DefinedValues[i].Target;
}
// Emit cross join
JoinAlgebraNode crossJoinNode = new JoinAlgebraNode();
crossJoinNode.Left = tableSpoolNode;
crossJoinNode.Right = concatAlgebraNode;
// Emit assert that ensures that the recursion level is <= 100.
expressionBuilder.Push(new RowBufferEntryExpression(incrementedRecursionLevel));
expressionBuilder.Push(LiteralExpression.FromInt32(100));
expressionBuilder.PushBinary(BinaryOperator.Greater);
CaseExpression caseExpression = new CaseExpression();
caseExpression.WhenExpressions = new ExpressionNode[1];
caseExpression.WhenExpressions[0] = expressionBuilder.Pop();
caseExpression.ThenExpressions = new ExpressionNode[1];
caseExpression.ThenExpressions[0] = LiteralExpression.FromInt32(0);
AssertAlgebraNode assertAlgebraNode = new AssertAlgebraNode();
assertAlgebraNode.Input = crossJoinNode;
assertAlgebraNode.AssertionType = AssertionType.BelowRecursionLimit;
assertAlgebraNode.Predicate = caseExpression;
recursiveNode = assertAlgebraNode;
}
#endregion
RowBufferEntry[] algebrizedOutput;
AlgebraNode algebrizedCte;
#region Combination
{
// Create concat node to combine anchor and recursive part.
ConcatAlgebraNode concatAlgebraNode = new ConcatAlgebraNode();
concatAlgebraNode.Inputs = new AlgebraNode[2];
concatAlgebraNode.Inputs[0] = anchorNode;
concatAlgebraNode.Inputs[1] = recursiveNode;
concatAlgebraNode.DefinedValues = new UnitedValueDefinition[anchorOutput.Length + 1];
concatAlgebraNode.DefinedValues[0] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[0].Target = new RowBufferEntry(anchorRecursionLevel.DataType);
concatAlgebraNode.DefinedValues[0].DependendEntries = new RowBufferEntry[] { anchorRecursionLevel, incrementedRecursionLevel };
for (int i = 0; i < anchorOutput.Length; i++)
{
concatAlgebraNode.DefinedValues[i + 1] = new UnitedValueDefinition();
concatAlgebraNode.DefinedValues[i + 1].Target = new RowBufferEntry(anchorOutput[i].DataType);
concatAlgebraNode.DefinedValues[i + 1].DependendEntries = new RowBufferEntry[] { anchorOutput[i], recursiveOutput[i] };
}
algebrizedOutput = new RowBufferEntry[concatAlgebraNode.DefinedValues.Length];
for (int i = 0; i < concatAlgebraNode.DefinedValues.Length; i++)
{
algebrizedOutput[i] = concatAlgebraNode.DefinedValues[i].Target;
}
// Assign the combination as the input to the primray spool
primaryTableSpool.Input = concatAlgebraNode;
// The primary spool represents the result of the "inlined" CTE.
algebrizedCte = primaryTableSpool;
}
#endregion
algebrizedCte.OutputList = algebrizedOutput;
return(algebrizedCte);
}
public override ExpressionNode VisitCaseExpression(CaseExpression expression)
{
// Ensure all nested expressions are fully resolved.
base.VisitCaseExpression(expression);
for (int i = 0; i < expression.WhenExpressions.Length; i++)
{
if (expression.WhenExpressions[i].ExpressionType == null || expression.ThenExpressions[i].ExpressionType == null)
{
return(expression);
}
}
if (expression.ElseExpression != null && expression.ElseExpression.ExpressionType == null)
{
return(expression);
}
// Ok, all nested expressions could be fully resolved. Lets validate the CASE expression.
// The semantic of CASE says that if no expression incl. ELSE does match the result is NULL.
// So having an ELSE expression that returns NULL is quite redundant.
LiteralExpression elseAsLiteral = expression.ElseExpression as LiteralExpression;
if (elseAsLiteral != null && elseAsLiteral.IsNullValue)
{
expression.ElseExpression = null;
}
// All WHEN expressions must evaluate to bool.
foreach (ExpressionNode whenExpression in expression.WhenExpressions)
{
if (whenExpression.ExpressionType != typeof(bool) && whenExpression.ExpressionType != typeof(DBNull))
{
_errorReporter.WhenMustEvaluateToBoolIfCaseInputIsOmitted(whenExpression);
}
}
// Check that all result expression incl. else share a common type.
//
// To do this and to support good error reporting we first try to find
// the best common type. Any needed conversions or type errors are
// ignored.
Type commonResultType = expression.ThenExpressions[0].ExpressionType;
for (int i = 1; i < expression.ThenExpressions.Length; i++)
{
commonResultType = _binder.ChooseBetterTypeConversion(commonResultType, expression.ThenExpressions[i].ExpressionType);
}
if (expression.ElseExpression != null)
{
commonResultType = _binder.ChooseBetterTypeConversion(expression.ElseExpression.ExpressionType, commonResultType);
}
// Now we know that commonResultType is the best type for all result expressions.
// Insert cast nodes for all expressions that have a different type but are
// implicit convertible and report errors for all expressions that not convertible.
if (expression.ElseExpression != null)
{
expression.ElseExpression = _binder.ConvertExpressionIfRequired(expression.ElseExpression, commonResultType);
}
for (int i = 0; i < expression.ThenExpressions.Length; i++)
{
expression.ThenExpressions[i] = _binder.ConvertExpressionIfRequired(expression.ThenExpressions[i], commonResultType);
}
expression.ResultType = commonResultType;
return(expression);
}
