internal override CqlBlock ToCqlBlock(bool[] requiredSlots, CqlIdentifiers identifiers, ref int blockAliasNum, ref List <WithRelationship> withRelationships)
{
// Get the projected slots and the boolean expressions
int totalSlots = requiredSlots.Length;
CellQuery cellQuery = LeftCellWrapper.RightCellQuery;
SlotInfo[] projectedSlots = new SlotInfo[totalSlots];
Debug.Assert(cellQuery.NumProjectedSlots + cellQuery.NumBoolVars == totalSlots,
"Wrong number of projected slots in node");
Debug.Assert(cellQuery.NumProjectedSlots == ProjectedSlotMap.Count,
"Different number of slots in cell query and what we have mappings for");
// Add the regular fields
for (int i = 0; i < cellQuery.NumProjectedSlots; i++)
{
ProjectedSlot slot = cellQuery.ProjectedSlotAt(i);
// If the slot is not null, we will project it
// For extents, we say that all requiredlots are the only the
// ones that are CLR non-null. Recall that "real" nulls are
// handled by having a CellConstant.Null in ConstantSlot
if (requiredSlots[i] && slot == null)
{
MemberPath memberPath = ProjectedSlotMap[i];
ConstantProjectedSlot defaultValue = new ConstantProjectedSlot(Domain.GetDefaultValueForMemberPath(memberPath, GetLeaves(), ViewgenContext.Config), memberPath);
cellQuery.FixMissingSlotAsDefaultConstant(i, defaultValue);
slot = defaultValue;
}
SlotInfo slotInfo = new SlotInfo(requiredSlots[i], slot != null,
slot, ProjectedSlotMap[i]);
projectedSlots[i] = slotInfo;
}
// Add the boolean fields
for (int boolNum = 0; boolNum < cellQuery.NumBoolVars; boolNum++)
{
BoolExpression expr = cellQuery.GetBoolVar(boolNum);
BooleanProjectedSlot boolSlot;
if (expr != null)
{
boolSlot = new BooleanProjectedSlot(expr, identifiers, boolNum);
}
else
{
boolSlot = new BooleanProjectedSlot(BoolExpression.False, identifiers, boolNum);
}
int slotIndex = BoolIndexToSlot(boolNum);
SlotInfo slotInfo = new SlotInfo(requiredSlots[slotIndex], expr != null,
boolSlot, null);
projectedSlots[slotIndex] = slotInfo;
}
// See if we are generating a query view and whether there are any colocated foreign keys for which
// we have to add With statements.
IEnumerable <SlotInfo> totalProjectedSlots = projectedSlots;
if ((cellQuery.Extent.EntityContainer.DataSpace == DataSpace.SSpace) &&
(this.m_cellWrapper.LeftExtent.BuiltInTypeKind == BuiltInTypeKind.EntitySet))
{
IEnumerable <StorageAssociationSetMapping> associationSetMaps =
this.ViewgenContext.EntityContainerMapping.GetRelationshipSetMappingsFor(this.m_cellWrapper.LeftExtent, cellQuery.Extent);
List <SlotInfo> foreignKeySlots = new List <SlotInfo>();
foreach (StorageAssociationSetMapping colocatedAssociationSetMap in associationSetMaps)
{
WithRelationship withRelationship;
if (TryGetWithRelationship(colocatedAssociationSetMap, this.m_cellWrapper.LeftExtent, cellQuery.SourceExtentMemberPath, ref foreignKeySlots, out withRelationship))
{
withRelationships.Add(withRelationship);
totalProjectedSlots = projectedSlots.Concat(foreignKeySlots);
}
}
}
ExtentCqlBlock result = new ExtentCqlBlock(cellQuery.Extent, cellQuery.SelectDistinctFlag, totalProjectedSlots.ToArray(),
cellQuery.WhereClause, identifiers, ++blockAliasNum);
return(result);
}
// effects: Generates a SlotInfo object for a slot of a join node. It
// uses the type of the join operation (opType), whether the slot is
// required by the parent or not (isRequiredSlot), the children of
// this node (children) and the number of the slotNum
private SlotInfo GetJoinSlotInfo(CellTreeOpType opType, bool isRequiredSlot,
List <CqlBlock> children, int slotNum, CqlIdentifiers identifiers)
{
if (false == isRequiredSlot)
{
// The slot will not be used. So we can set the projected slot to be null
SlotInfo unrequiredSlotInfo = new SlotInfo(false, false, null, GetMemberPath(slotNum));
return(unrequiredSlotInfo);
}
// For a required slot, determine the child who is contributing to this value
int childDefiningSlot = -1;
CaseStatement caseForOuterJoins = null;
for (int childNum = 0; childNum < children.Count; childNum++)
{
CqlBlock child = children[childNum];
if (false == child.IsProjected(slotNum))
{
continue;
}
// For keys, we can pick any child block. So the first
// one that we find is fine as well
if (IsKeySlot(slotNum))
{
childDefiningSlot = childNum;
break;
}
else if (opType == CellTreeOpType.IJ)
{
// For Inner Joins, most of the time, the entries will be
// the same in all the children. However, in some cases,
// we will end up with NULL in one child and an actual
// value in another -- we should pick up the actual value in that case
childDefiningSlot = GetInnerJoinChildForSlot(children, slotNum);
break;
}
else
{
// For LOJs, we generate a case statement if more than
// one child generates the value - until then we do not
// create the caseForOuterJoins object
if (childDefiningSlot != -1)
{
// We really need a case statement now
// We have the value being generated by another child
// We need to fetch the variable from the appropriate child
Debug.Assert(false == IsBoolSlot(slotNum), "Boolean slots cannot come from two children");
if (caseForOuterJoins == null)
{
MemberPath outputMember = GetMemberPath(slotNum);
caseForOuterJoins = new CaseStatement(outputMember);
// Add the child that we had not added in the first shot
AddCaseForOuterJoins(caseForOuterJoins, children[childDefiningSlot], slotNum, identifiers);
}
AddCaseForOuterJoins(caseForOuterJoins, child, slotNum, identifiers);
}
childDefiningSlot = childNum;
}
}
MemberPath memberPath = GetMemberPath(slotNum);
ProjectedSlot slot = null;
// Generate the slot value -- case statement slot, or a qualified slot or null or false.
// If case statement slot has nothing, treat it as null/empty.
if (caseForOuterJoins != null && (caseForOuterJoins.Clauses.Count > 0 || caseForOuterJoins.ElseValue != null))
{
caseForOuterJoins.Simplify();
slot = new CaseStatementProjectedSlot(caseForOuterJoins, null);
}
else if (childDefiningSlot >= 0)
{
slot = children[childDefiningSlot].QualifySlotWithBlockAlias(slotNum);
}
else
{
// need to produce output slot, but don't have a value
// output NULL for fields or False for bools
if (IsBoolSlot(slotNum))
{
slot = new BooleanProjectedSlot(BoolExpression.False, identifiers, SlotToBoolIndex(slotNum));
}
else
{
slot = new ConstantProjectedSlot(Domain.GetDefaultValueForMemberPath(memberPath, GetLeaves(), ViewgenContext.Config), memberPath);
}
}
// We need to ensure that _from variables are never null since
// view generation uses 2-valued boolean logic.
// They can become null in outer joins. We compensate for it by
// adding AND NOT NULL condition on boolean slots coming from outer joins.
bool enforceNotNull = IsBoolSlot(slotNum) &&
((opType == CellTreeOpType.LOJ && childDefiningSlot > 0) ||
opType == CellTreeOpType.FOJ);
// We set isProjected to be true since we have come up with some value for it
SlotInfo slotInfo = new SlotInfo(true, true, slot, memberPath, enforceNotNull);
return(slotInfo);
}