/// <summary>
/// Initializes a <see cref="CqlBlock"/> with the SELECT (<paramref name="slotInfos"/>), FROM (<paramref name="children"/>),
/// WHERE (<paramref name="whereClause"/>), AS (<paramref name="blockAliasNum"/>).
/// </summary>
protected CqlBlock(SlotInfo[] slotInfos, List<CqlBlock> children, BoolExpression whereClause, CqlIdentifiers identifiers, int blockAliasNum)
{
m_slots = new ReadOnlyCollection<SlotInfo>(slotInfos);
m_children = new ReadOnlyCollection<CqlBlock>(children);
m_whereClause = whereClause;
m_blockAlias = identifiers.GetBlockAlias(blockAliasNum);
}
/// <summary>
/// Creates a join block (type given by <paramref name="opType"/>) with SELECT (<paramref name="slotInfos"/>), FROM (<paramref name="children"/>),
/// ON (<paramref name="onClauses"/> - one for each child except 0th), WHERE (true), AS (<paramref name="blockAliasNum"/>).
/// </summary>
internal JoinCqlBlock(CellTreeOpType opType,
SlotInfo[] slotInfos,
List<CqlBlock> children,
List<OnClause> onClauses,
CqlIdentifiers identifiers,
int blockAliasNum)
: base(slotInfos, children, BoolExpression.True, identifiers, blockAliasNum)
{
m_opType = opType;
m_onClauses = onClauses;
}
/// <summary>
/// Creates an cql block representing the <paramref name="extent"/> (the FROM part).
/// SELECT is given by <paramref name="slots"/>, WHERE by <paramref name="whereClause"/> and AS by <paramref name="blockAliasNum"/>.
/// </summary>
internal ExtentCqlBlock(EntitySetBase extent,
CellQuery.SelectDistinct selectDistinct,
SlotInfo[] slots,
BoolExpression whereClause,
CqlIdentifiers identifiers,
int blockAliasNum)
: base(slots, EmptyChildren, whereClause, identifiers, blockAliasNum)
{
m_extent = extent;
m_nodeTableAlias = identifiers.GetBlockAlias();
m_selectDistinct = selectDistinct;
}
/// <summary>
/// Given the slot (<paramref name="foundSlot"/>) and its corresponding case statement (<paramref name="thisCaseStatement"/>),
/// generates the slotinfos for the cql block producing the case statement.
/// </summary>
private SlotInfo[] CreateSlotInfosForCaseStatement(bool[] parentRequiredSlots,
int foundSlot,
CqlBlock childBlock,
CaseStatement thisCaseStatement,
IEnumerable<WithRelationship> withRelationships)
{
int numSlotsAddedByChildBlock = childBlock.Slots.Count - TotalSlots;
SlotInfo[] slotInfos = new SlotInfo[TotalSlots + numSlotsAddedByChildBlock];
for (int slotNum = 0; slotNum < TotalSlots; slotNum++)
{
bool isProjected = childBlock.IsProjected(slotNum);
bool isRequiredByParent = parentRequiredSlots[slotNum];
ProjectedSlot slot = childBlock.SlotValue(slotNum);
MemberPath outputMember = GetOutputMemberPath(slotNum);
if (slotNum == foundSlot)
{
// We need a case statement instead for this slot that we
// are handling right now
Debug.Assert(isRequiredByParent, "Case result not needed by parent");
// Get a case statement with all slots replaced by aliases slots
CaseStatement newCaseStatement = thisCaseStatement.DeepQualify(childBlock);
slot = new CaseStatementProjectedSlot(newCaseStatement, withRelationships);
isProjected = true; // We are projecting this slot now
}
else if (isProjected && isRequiredByParent)
{
// We only alias something that is needed and is being projected by the child.
// It is a qualified slot into the child block.
slot = childBlock.QualifySlotWithBlockAlias(slotNum);
}
// For slots, if it is not required by the parent, we want to
// set the isRequiredByParent for this slot to be
// false. Furthermore, we do not want to introduce any "NULL
// AS something" at this stage for slots not being
// projected. So if the child does not project that slot, we
// declare it as not being required by the parent (if such a
// NULL was needed, it would have been pushed all the way
// down to a non-case block.
// Essentially, from a Case statement's parent perspective,
// it is saying "If you can produce a slot either by yourself
// or your children, please do. Otherwise, do not concoct anything"
SlotInfo slotInfo = new SlotInfo(isRequiredByParent && isProjected, isProjected, slot, outputMember);
slotInfos[slotNum] = slotInfo;
}
for (int i = TotalSlots; i < TotalSlots + numSlotsAddedByChildBlock; i++)
{
QualifiedSlot childAddedSlot = childBlock.QualifySlotWithBlockAlias(i);
slotInfos[i] = new SlotInfo(true, true, childAddedSlot, childBlock.MemberPath(i));
}
return slotInfos;
}
/// <summary>
/// Creates a <see cref="CqlBlock"/> containing the case statememt for the <paramref name="caseSlot"/> and projecting other slots as is from its child (input). CqlBlock with SELECT (slots),
/// </summary>
/// <param name="caseSlot">indicates which slot in <paramref name="slots"/> corresponds to the case statement being generated by this block</param>
internal CaseCqlBlock(SlotInfo[] slots, int caseSlot, CqlBlock child, BoolExpression whereClause, CqlIdentifiers identifiers, int blockAliasNum)
: base(slots, new List<CqlBlock>(new CqlBlock[] { child }), whereClause, identifiers, blockAliasNum)
{
m_caseSlotInfo = slots[caseSlot];
}
/// <summary>
/// Creates a union block with SELECT (<paramref name="slotInfos"/>), FROM (<paramref name="children"/>), WHERE (true), AS (<paramref name="blockAliasNum"/>).
/// </summary>
internal UnionCqlBlock(SlotInfo[] slotInfos, List<CqlBlock> children, CqlIdentifiers identifiers, int blockAliasNum)
: base(slotInfos, children, BoolExpression.True, identifiers, blockAliasNum)
{ }
