internal override DbExpression AsCqt(bool isTopLevel)
{
// The FROM part:
// - build a tree of binary joins out of the inputs (this.Children).
// - update each child block with its relative position in the join tree,
// so that QualifiedSlot and QualifiedCellIdBoolean objects could find their
// designated block areas inside the cumulative join row passed into their AsCqt(row) method.
CqlBlock leftmostBlock = this.Children[0];
DbExpression left = leftmostBlock.AsCqt(false);
List <string> joinTreeCtxParentQualifiers = new List <string>();
for (int i = 1; i < this.Children.Count; ++i)
{
// Join the current left expression (a tree) to the current right block.
CqlBlock rightBlock = this.Children[i];
DbExpression right = rightBlock.AsCqt(false);
Func <DbExpression, DbExpression, DbExpression> joinConditionFunc = m_onClauses[i - 1].AsCqt;
DbJoinExpression join;
switch (m_opType)
{
case CellTreeOpType.FOJ:
join = left.FullOuterJoin(right, joinConditionFunc);
break;
case CellTreeOpType.IJ:
join = left.InnerJoin(right, joinConditionFunc);
break;
case CellTreeOpType.LOJ:
join = left.LeftOuterJoin(right, joinConditionFunc);
break;
default:
Debug.Fail("Unknown operator");
return(null);
}
if (i == 1)
{
// Assign the joinTreeContext to the leftmost block.
leftmostBlock.SetJoinTreeContext(joinTreeCtxParentQualifiers, join.Left.VariableName);
}
else
{
// Update the joinTreeCtxParentQualifiers.
// Note that all blocks that already participate in the left expression tree share the same copy of the joinTreeContext.
joinTreeCtxParentQualifiers.Add(join.Left.VariableName);
}
// Assign the joinTreeContext to the right block.
rightBlock.SetJoinTreeContext(joinTreeCtxParentQualifiers, join.Right.VariableName);
left = join;
}
// The SELECT part.
return(left.Select(row => GenerateProjectionCqt(row, false)));
}
internal override DbExpression AsCqt(bool isTopLevel)
{
CqlBlock child1 = this.Children[0];
DbExpression dbExpression = child1.AsCqt(false);
List <string> stringList = new List <string>();
for (int index = 1; index < this.Children.Count; ++index)
{
CqlBlock child2 = this.Children[index];
DbExpression right = child2.AsCqt(false);
Func <DbExpression, DbExpression, DbExpression> joinCondition = new Func <DbExpression, DbExpression, DbExpression>(this.m_onClauses[index - 1].AsCqt);
DbJoinExpression dbJoinExpression;
switch (this.m_opType)
{
case CellTreeOpType.FOJ:
dbJoinExpression = dbExpression.FullOuterJoin(right, joinCondition);
break;
case CellTreeOpType.LOJ:
dbJoinExpression = dbExpression.LeftOuterJoin(right, joinCondition);
break;
case CellTreeOpType.IJ:
dbJoinExpression = dbExpression.InnerJoin(right, joinCondition);
break;
default:
return((DbExpression)null);
}
if (index == 1)
{
child1.SetJoinTreeContext((IList <string>)stringList, dbJoinExpression.Left.VariableName);
}
else
{
stringList.Add(dbJoinExpression.Left.VariableName);
}
child2.SetJoinTreeContext((IList <string>)stringList, dbJoinExpression.Right.VariableName);
dbExpression = (DbExpression)dbJoinExpression;
}
return((DbExpression)dbExpression.Select <DbExpression>((Func <DbExpression, DbExpression>)(row => this.GenerateProjectionCqt(row, false))));
}
