List <FoundEquality> SearchForFields(SelectQuery.TableSource manySource, SelectQuery.JoinedTable join)
{
var key = Tuple.Create(manySource, join.Table);
List <FoundEquality> found = null;
if (_fieldPairCache != null && _fieldPairCache.TryGetValue(key, out found))
{
return(found);
}
for (var i1 = 0; i1 < join.Condition.Conditions.Count; i1++)
{
var c = join.Condition.Conditions[i1];
if (c.IsOr)
{
found = null;
break;
}
if (c.ElementType != QueryElementType.Condition ||
c.Predicate.ElementType != QueryElementType.ExprExprPredicate ||
((SelectQuery.Predicate.ExprExpr)c.Predicate).Operator != SelectQuery.Predicate.Operator.Equal)
{
continue;
}
var predicate = (SelectQuery.Predicate.ExprExpr)c.Predicate;
var equality = new FoundEquality();
if (!MatchFields(manySource, join.Table,
GetUnderlayingField(predicate.Expr1),
GetUnderlayingField(predicate.Expr2),
equality))
{
continue;
}
equality.OneCondition = c;
if (found == null)
{
found = new List <FoundEquality>();
}
found.Add(equality);
}
if (_fieldPairCache == null)
{
_fieldPairCache = new Dictionary <Tuple <SelectQuery.TableSource, SelectQuery.TableSource>, List <FoundEquality> >();
}
_fieldPairCache.Add(key, found);
return(found);
}
bool MatchFields(SelectQuery.TableSource manySource, SelectQuery.TableSource oneSource, VirtualField field1, VirtualField field2, FoundEquality equality)
{
if (field1 == null || field2 == null)
{
return(false);
}
DetectField(manySource, oneSource, field1, equality);
DetectField(manySource, oneSource, field2, equality);
return(equality.OneField != null && equality.ManyField != null);
}
void DetectField(SelectQuery.TableSource manySource, SelectQuery.TableSource oneSource, VirtualField field, FoundEquality equality)
{
field = GetNewField(field);
if (oneSource.Source.SourceID == field.SourceID)
{
equality.OneField = field;
}
else if (manySource.Source.SourceID == field.SourceID)
{
equality.ManyField = field;
}
else
{
equality.ManyField = MapToSource(manySource, field, manySource.Source.SourceID);
}
}
void DetectField(SqlTableSource?manySource, SqlTableSource oneSource, VirtualField field, FoundEquality equality)
{
field = GetNewField(field);
if (oneSource.Source.SourceID == field.SourceID)
{
equality.OneField = field;
}
else if (oneSource.Source is SelectQuery select && select.Select.From.Tables.Count == 1 && select.Select.From.Tables[0].SourceID == field.SourceID)
{
equality.OneField = field;
}
