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 InFragment TryMergeTwoInFragments(InFragment infLeft, InFragment infRight)
{
if (infLeft.Argument.Equals(infRight.Argument) &&
(infLeft.IsNegated == infRight.IsNegated) && (!infLeft.IsNegated))
{
infLeft.InList.AddRange(infRight.InList);
return(infLeft);
}
return(null);
}
public override SqlFragment Visit(DbInExpression expression)
{
SqlFragment sf = expression.Item.Accept(this);
InFragment inf = new InFragment();
inf.Argument = sf;
for (int i = 0; i < expression.List.Count; i++)
{
LiteralFragment lf = Visit(expression.List[i] as DbConstantExpression) as LiteralFragment;
inf.InList.Add(lf);
}
return(inf);
}
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 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 void Visit(InFragment f)
{
}