protected InFragment TryMergeTwoBinaryFragments(BinaryFragment left, BinaryFragment right)
{
if ((left.IsNegated == right.IsNegated) && (!left.IsNegated) &&
(left.Operator == "=") && (right.Operator == "="))
{
ColumnFragment cf;
LiteralFragment lf;
GetBinaryFragmentPartsForIn(left, out lf, out cf);
if ((lf != null) && (cf != null))
{
ColumnFragment cf2;
LiteralFragment lf2;
GetBinaryFragmentPartsForIn(right, out lf2, out cf2);
if ((lf2 != null) && (cf2 != null) && cf.Equals(cf2))
{
InFragment inf = new InFragment();
inf.Argument = cf;
inf.InList.Add(lf);
inf.InList.Add(lf2);
return(inf);
}
}
}
return(null);
}
protected void GetBinaryFragmentPartsForIn(BinaryFragment bf, out LiteralFragment lf, out ColumnFragment cf)
{
cf = bf.Right as ColumnFragment;
lf = bf.Left as LiteralFragment;
if (lf == null)
{
lf = bf.Right as LiteralFragment;
cf = bf.Left as ColumnFragment;
}
}
protected override SqlFragment VisitBinaryExpression(DbExpression left, DbExpression right, string op)
{
BinaryFragment f = new BinaryFragment();
f.Operator = op;
f.Left = left.Accept(this);
f.WrapLeft = ShouldWrapExpression(left);
if (f.Left is ColumnFragment)
{
_columnsVisited.Push((( DbPropertyExpression )left).Property);
}
f.Right = right.Accept(this);
if (f.Left is ColumnFragment)
{
_columnsVisited.Pop();
}
f.WrapRight = ShouldWrapExpression(right);
return(f);
}
protected InFragment TryMergeBinaryFragmentAndInFragment(BinaryFragment bf, InFragment inf)
{
if (!bf.IsNegated && (bf.Operator == "="))
{
ColumnFragment cf;
LiteralFragment lf;
GetBinaryFragmentPartsForIn(bf, out lf, out cf);
if ((lf != null) && (cf != null))
{
if (inf.Argument.Equals(cf))
{
if (!inf.InList.Contains(lf))
{
inf.InList.Add(lf);
}
return(inf);
}
}
}
return(null);
}
protected virtual SqlFragment VisitBinaryExpression(DbExpression left, DbExpression right, string op)
{
// Optimization: try to use 'like' instead of 'locate' (Edm.IndexOf) for these
// cases: (like 'word%'), (like '%word') & (like '%word%').
LikeFragment like = TryPromoteToLike(left, right, op);
if (like != null)
{
return(like);
}
// normal flow
BinaryFragment f = new BinaryFragment();
f.Operator = op;
f.Left = left.Accept(this);
f.WrapLeft = ShouldWrapExpression(left);
f.Right = right.Accept(this);
f.WrapRight = ShouldWrapExpression(right);
// Optimization, try to promote to In expression
// NOTE: In EF6, this optimization is already done, we just implement Visit(DbInExpression).
return(f);
}
protected virtual SqlFragment TryToPromoteToIn(BinaryFragment bf)
{
// TODO: Remember Morgan's theorem
// Only try to merge if they are OR'ed.
if ((bf.Operator == "OR"))
{
InFragment inf = bf.Left as InFragment;
InFragment inf2 = bf.Right as InFragment;
if (inf == null)
{
BinaryFragment bfLeft = bf.Left as BinaryFragment;
if (bfLeft == null)
{
return(bf);
}
if (inf2 == null)
{
// try to create a new infragment
BinaryFragment bfRight = bf.Right as BinaryFragment;
if (bfRight == null)
{
return(bf);
}
InFragment inff = TryMergeTwoBinaryFragments(bfLeft, bfRight);
if (inff != null)
{
return(inff);
}
}
else
{
// try to merge an existing infragment & a binaryfragment.
SqlFragment sf = TryMergeBinaryFragmentAndInFragment(bfLeft, inf2);
if (sf != null)
{
return(sf);
}
}
}
else if (inf2 == null)
{
BinaryFragment bfRight = bf.Right as BinaryFragment;
if (bfRight == null)
{
return(bf);
}
else
{
// try to merge an existing infragment & a binaryfragment.
SqlFragment sf = TryMergeBinaryFragmentAndInFragment(bfRight, inf);
if (sf != null)
{
return(sf);
}
}
}
else
{
// try to merge both InFragments
SqlFragment sf = TryMergeTwoInFragments(inf, inf2);
if (sf != null)
{
return(sf);
}
}
}
return(bf);
}
public override SqlFragment Visit(DbApplyExpression expression)
{
DbExpressionBinding inputBinding = expression.Input;
InputFragment input = VisitInputExpression(inputBinding.Expression, inputBinding.VariableName, inputBinding.VariableType);
DbExpressionBinding applyBinding = expression.Apply;
InputFragment apply = VisitInputExpression(applyBinding.Expression, applyBinding.VariableName, applyBinding.VariableType);
SelectStatement select = new SelectStatement(this);
bool isInputSelect = false;
if (!(input is TableFragment))
{
input.Wrap(scope);
isInputSelect = true;
}
apply.Wrap(scope);
select.From = input;
select.Wrap(scope);
if (apply is SelectStatement)
{
SelectStatement applySel = apply as SelectStatement;
foreach (ColumnFragment f in applySel.Columns)
{
SelectStatement newColSelect = new SelectStatement(this);
newColSelect.From = applySel.From;
newColSelect.Where = applySel.Where;
if (isInputSelect)
{
VisitAndReplaceTableName(newColSelect.Where, (input as SelectStatement).From.Name, input.Name, null);
}
newColSelect.Limit = applySel.Limit;
newColSelect.OrderBy = applySel.OrderBy;
newColSelect.Skip = applySel.Skip;
newColSelect.GroupBy = applySel.GroupBy;
newColSelect.IsDistinct = applySel.IsDistinct;
newColSelect.Columns.Add(f);
newColSelect.Wrap(scope);
scope.Add(applySel.From.Name, applySel.From);
ColumnFragment newCol = new ColumnFragment(apply.Name, f.ColumnName);
newCol.Literal = newColSelect;
newCol.PushInput(newCol.ColumnName);
newCol.PushInput(apply.Name);
select.AddColumn(newCol, scope);
if (string.IsNullOrEmpty(newCol.ColumnAlias))
{
newColSelect.Name = newCol.ColumnName;
newCol.ColumnAlias = newCol.ColumnName;
}
scope.Remove(newColSelect);
}
scope.Remove(applySel.From);
scope.Remove(apply);
}
else if (apply is UnionFragment)
{
UnionFragment uf = apply as UnionFragment;
if (uf.Left == null || uf.Right == null)
{
throw new Exception("Union fragment is not properly formed.");
}
var left = uf.Left as SelectStatement;
var right = uf.Right as SelectStatement;
if (left == null || right == null)
{
throw new NotImplementedException();
}
var whereleft = left.Where as BinaryFragment;
var whereright = right.Where as BinaryFragment;
if (whereleft == null || whereright == null)
{
throw new NotImplementedException();
}
LiteralFragment literalFragmentWhere = null;
//checking where left
if (whereleft.Left is ColumnFragment && whereleft.Right is ColumnFragment)
{
// we replace the where part for a dummy one
if (whereright.Left is ColumnFragment && whereright.Right is ColumnFragment)
{
literalFragmentWhere = new LiteralFragment("1 = 1");
}
}
if (literalFragmentWhere == null)
{
throw new NotImplementedException();
}
var leftouterjoin = new JoinFragment();
leftouterjoin.JoinType = Metadata.GetOperator(DbExpressionKind.LeftOuterJoin);
leftouterjoin.Name = apply.Name;
// validating that column fragment on the left matches the name
// for the input fragment
var leftColumnFragment = whereleft.Left as ColumnFragment;
if (leftColumnFragment == null)
{
throw new NotImplementedException();
}
if (!leftColumnFragment.TableName.Equals(input.Name))
{
new NotImplementedException();
}
var conditionJoin = new BinaryFragment();
conditionJoin.Left = whereleft.Left;
//update to the new reference
var newColumnFragment = whereright.Right as ColumnFragment;
if (newColumnFragment != null)
{
newColumnFragment.TableName = uf.Name;
}
conditionJoin.Right = newColumnFragment;
conditionJoin.Operator = whereleft.Operator;
leftouterjoin.Condition = conditionJoin;
(uf.Left as SelectStatement).Where = literalFragmentWhere;
(uf.Right as SelectStatement).Where = literalFragmentWhere;
leftouterjoin.Left = input;
leftouterjoin.Right = uf;
return(leftouterjoin);
}
return(select);
}
public void Visit(BinaryFragment f)
{
}