private CellTreeNode ConvertUnionsToNormalizedLOJs(CellTreeNode rootNode)
{
// Recursively, transform the subtrees rooted at rootNode's children.
for (var i = 0; i < rootNode.Children.Count; i++)
{
// Method modifies input as well.
rootNode.Children[i] = ConvertUnionsToNormalizedLOJs(rootNode.Children[i]);
}
// We rewrite only LOJs.
if (rootNode.OpType != CellTreeOpType.LOJ
|| rootNode.Children.Count < 2)
{
return rootNode;
}
// Create the resulting LOJ node.
var result = new OpCellTreeNode(m_viewgenContext, rootNode.OpType);
// Create working collection for the LOJ children.
var children = new List<CellTreeNode>();
// If rootNode looks something like ((V0 IJ V1) LOJ V2 LOJ V3),
// and it turns out that there are FK associations from V2 or V3 pointing, let's say at V0,
// then we want to rewrite the result as (V1 IJ (V0 LOJ V2 LOJ V3)).
// If we don't do this, then plan compiler won't have a chance to eliminate LOJ V2 LOJ V3.
// Hence, flatten the first child or rootNode if it's IJ, but remember that its parts are driving nodes for the LOJ,
// so that we don't accidentally nest them.
OpCellTreeNode resultIJDriver = null;
HashSet<CellTreeNode> resultIJDriverChildren = null;
if (rootNode.Children[0].OpType
== CellTreeOpType.IJ)
{
// Create empty resultIJDriver node and add it as the first child (driving) into the LOJ result.
resultIJDriver = new OpCellTreeNode(m_viewgenContext, rootNode.Children[0].OpType);
result.Add(resultIJDriver);
children.AddRange(rootNode.Children[0].Children);
resultIJDriverChildren = new HashSet<CellTreeNode>(rootNode.Children[0].Children);
}
else
{
result.Add(rootNode.Children[0]);
}
// Flatten unions in non-driving nodes: (V0 LOJ (V1 Union V2 Union V3)) -> (V0 LOJ V1 LOJ V2 LOJ V3)
foreach (var child in rootNode.Children.Skip(1))
{
var opNode = child as OpCellTreeNode;
if (opNode != null
&& opNode.OpType == CellTreeOpType.Union)
{
children.AddRange(opNode.Children);
}
else
{
children.Add(child);
}
}
// A dictionary that maps an extent to the nodes that are from that extent.
// We want a ref comparer here.
var extentMap = new KeyToListMap<EntitySet, LeafCellTreeNode>(EqualityComparer<EntitySet>.Default);
// Note that we skip non-leaf nodes (non-leaf nodes don't have FKs) and attach them directly to the result.
foreach (var child in children)
{
var leaf = child as LeafCellTreeNode;
if (leaf != null)
{
EntitySetBase extent = GetLeafNodeTable(leaf);
if (extent != null)
{
extentMap.Add((EntitySet)extent, leaf);
}
}
else
{
if (resultIJDriverChildren != null
&& resultIJDriverChildren.Contains(child))
{
resultIJDriver.Add(child);
}
else
{
result.Add(child);
}
}
}
// We only deal with simple cases - one node per extent, remove the rest from children and attach directly to result.
var nonTrivial = extentMap.KeyValuePairs.Where(m => m.Value.Count > 1).ToArray();
foreach (var m in nonTrivial)
{
extentMap.RemoveKey(m.Key);
foreach (var n in m.Value)
{
if (resultIJDriverChildren != null
&& resultIJDriverChildren.Contains(n))
{
resultIJDriver.Add(n);
}
else
{
result.Add(n);
}
}
}
Debug.Assert(extentMap.KeyValuePairs.All(m => m.Value.Count == 1), "extentMap must map to single nodes only.");
// Walk the extents in extentMap and for each extent build PK -> FK1(PK1), FK2(PK2), ... map
// where PK is the primary key of the left extent, and FKn(PKn) is an FK of a right extent that
// points to the PK of the left extent and is based on the PK columns of the right extent.
// Example:
// table tBaseType(Id int, c1 int), PK = (tBaseType.Id)
// table tDerivedType1(Id int, c2 int), PK1 = (tDerivedType1.Id), FK1 = (tDerivedType1.Id -> tBaseType.Id)
// table tDerivedType2(Id int, c3 int), PK2 = (tDerivedType2.Id), FK2 = (tDerivedType2.Id -> tBaseType.Id)
// Will produce:
// (tBaseType) -> (tDerivedType1, tDerivedType2)
var pkFkMap = new KeyToListMap<EntitySet, EntitySet>(EqualityComparer<EntitySet>.Default);
// Also for each extent in extentMap, build another map (extent) -> (LOJ node).
// It will be used to construct the nesting in the next step.
var extentLOJs = new Dictionary<EntitySet, OpCellTreeNode>(EqualityComparer<EntitySet>.Default);
foreach (var extentInfo in extentMap.KeyValuePairs)
{
var principalExtent = extentInfo.Key;
foreach (var fkExtent in GetFKOverPKDependents(principalExtent))
{
// Only track fkExtents that are in extentMap.
ReadOnlyCollection<LeafCellTreeNode> nodes;
if (extentMap.TryGetListForKey(fkExtent, out nodes))
{
// Make sure that we are not adding resultIJDriverChildren as FK dependents - we do not want them to get nested.
if (resultIJDriverChildren == null
|| !resultIJDriverChildren.Contains(nodes.Single()))
{
pkFkMap.Add(principalExtent, fkExtent);
}
}
}
var extentLojNode = new OpCellTreeNode(m_viewgenContext, CellTreeOpType.LOJ);
extentLojNode.Add(extentInfo.Value.Single());
extentLOJs.Add(principalExtent, extentLojNode);
}
// Construct LOJ nesting inside extentLOJs based on the information in pkFkMap.
// Also, track nested extents using nestedExtents.
// Example:
// We start with nestedExtents empty extentLOJs as such:
// tBaseType -> LOJ(BaseTypeNode)
// tDerivedType1 -> LOJ(DerivedType1Node)*
// tDerivedType2 -> LOJ(DerivedType2Node)**
// Note that * and ** represent object references. So each time something is nested,
// we don't clone, but nest the original LOJ. When we get to processing the extent of that LOJ,
// we might add other children to that nested LOJ.
// As we walk pkFkMap, we end up with this:
// tBaseType -> LOJ(BaseTypeNode, LOJ(DerivedType1Node)*, LOJ(DerivedType2Node)**)
// tDerivedType1 -> LOJ(DerivedType1Node)*
// tDerivedType2 -> LOJ(DerivedType2Node)**
// nestedExtens = (tDerivedType1, tDerivedType2)
var nestedExtents = new Dictionary<EntitySet, EntitySet>(EqualityComparer<EntitySet>.Default);
foreach (var m in pkFkMap.KeyValuePairs)
{
var principalExtent = m.Key;
foreach (var fkExtent in m.Value)
{
OpCellTreeNode fkExtentLOJ;
if (extentLOJs.TryGetValue(fkExtent, out fkExtentLOJ) &&
// make sure we don't nest twice and we don't create a cycle.
!nestedExtents.ContainsKey(fkExtent)
&& !CheckLOJCycle(fkExtent, principalExtent, nestedExtents))
{
extentLOJs[m.Key].Add(fkExtentLOJ);
nestedExtents.Add(fkExtent, principalExtent);
}
}
}
// Now we need to grab the LOJs that have not been nested and add them to the result.
// All LOJs that have been nested must be somewhere inside the LOJs that have not been nested,
// so they as well end up in the result as part of the unnested ones.
foreach (var m in extentLOJs)
{
if (!nestedExtents.ContainsKey(m.Key))
{
// extentLOJ represents (Vx LOJ Vy LOJ(Vm LOJ Vn)) where Vx is the original node from rootNode.Children or resultIJDriverChildren.
var extentLOJ = m.Value;
if (resultIJDriverChildren != null
&& resultIJDriverChildren.Contains(extentLOJ.Children[0]))
{
resultIJDriver.Add(extentLOJ);
}
else
{
result.Add(extentLOJ);
}
}
}
return result.Flatten();
}
private CellTreeNode ConvertUnionsToNormalizedLOJs(CellTreeNode rootNode)
{
// Recursively, transform the subtrees rooted at rootNode's children.
for (var i = 0; i < rootNode.Children.Count; i++)
{
// Method modifies input as well.
rootNode.Children[i] = ConvertUnionsToNormalizedLOJs(rootNode.Children[i]);
}
// We rewrite only LOJs.
if (rootNode.OpType != CellTreeOpType.LOJ ||
rootNode.Children.Count < 2)
{
return(rootNode);
}
// Create the resulting LOJ node.
var result = new OpCellTreeNode(m_viewgenContext, rootNode.OpType);
// Create working collection for the LOJ children.
var children = new List <CellTreeNode>();
// If rootNode looks something like ((V0 IJ V1) LOJ V2 LOJ V3),
// and it turns out that there are FK associations from V2 or V3 pointing, let's say at V0,
// then we want to rewrite the result as (V1 IJ (V0 LOJ V2 LOJ V3)).
// If we don't do this, then plan compiler won't have a chance to eliminate LOJ V2 LOJ V3.
// Hence, flatten the first child or rootNode if it's IJ, but remember that its parts are driving nodes for the LOJ,
// so that we don't accidentally nest them.
OpCellTreeNode resultIJDriver = null;
HashSet <CellTreeNode> resultIJDriverChildren = null;
if (rootNode.Children[0].OpType
== CellTreeOpType.IJ)
{
// Create empty resultIJDriver node and add it as the first child (driving) into the LOJ result.
resultIJDriver = new OpCellTreeNode(m_viewgenContext, rootNode.Children[0].OpType);
result.Add(resultIJDriver);
children.AddRange(rootNode.Children[0].Children);
resultIJDriverChildren = new HashSet <CellTreeNode>(rootNode.Children[0].Children);
}
else
{
result.Add(rootNode.Children[0]);
}
// Flatten unions in non-driving nodes: (V0 LOJ (V1 Union V2 Union V3)) -> (V0 LOJ V1 LOJ V2 LOJ V3)
foreach (var child in rootNode.Children.Skip(1))
{
var opNode = child as OpCellTreeNode;
if (opNode != null &&
opNode.OpType == CellTreeOpType.Union)
{
children.AddRange(opNode.Children);
}
else
{
children.Add(child);
}
}
// A dictionary that maps an extent to the nodes that are from that extent.
// We want a ref comparer here.
var extentMap = new KeyToListMap <EntitySet, LeafCellTreeNode>(EqualityComparer <EntitySet> .Default);
// Note that we skip non-leaf nodes (non-leaf nodes don't have FKs) and attach them directly to the result.
foreach (var child in children)
{
var leaf = child as LeafCellTreeNode;
if (leaf != null)
{
EntitySetBase extent = GetLeafNodeTable(leaf);
if (extent != null)
{
extentMap.Add((EntitySet)extent, leaf);
}
}
else
{
if (resultIJDriverChildren != null &&
resultIJDriverChildren.Contains(child))
{
resultIJDriver.Add(child);
}
else
{
result.Add(child);
}
}
}
// We only deal with simple cases - one node per extent, remove the rest from children and attach directly to result.
var nonTrivial = extentMap.KeyValuePairs.Where(m => m.Value.Count > 1).ToArray();
foreach (var m in nonTrivial)
{
extentMap.RemoveKey(m.Key);
foreach (var n in m.Value)
{
if (resultIJDriverChildren != null &&
resultIJDriverChildren.Contains(n))
{
resultIJDriver.Add(n);
}
else
{
result.Add(n);
}
}
}
Debug.Assert(extentMap.KeyValuePairs.All(m => m.Value.Count == 1), "extentMap must map to single nodes only.");
// Walk the extents in extentMap and for each extent build PK -> FK1(PK1), FK2(PK2), ... map
// where PK is the primary key of the left extent, and FKn(PKn) is an FK of a right extent that
// points to the PK of the left extent and is based on the PK columns of the right extent.
// Example:
// table tBaseType(Id int, c1 int), PK = (tBaseType.Id)
// table tDerivedType1(Id int, c2 int), PK1 = (tDerivedType1.Id), FK1 = (tDerivedType1.Id -> tBaseType.Id)
// table tDerivedType2(Id int, c3 int), PK2 = (tDerivedType2.Id), FK2 = (tDerivedType2.Id -> tBaseType.Id)
// Will produce:
// (tBaseType) -> (tDerivedType1, tDerivedType2)
var pkFkMap = new KeyToListMap <EntitySet, EntitySet>(EqualityComparer <EntitySet> .Default);
// Also for each extent in extentMap, build another map (extent) -> (LOJ node).
// It will be used to construct the nesting in the next step.
var extentLOJs = new Dictionary <EntitySet, OpCellTreeNode>(EqualityComparer <EntitySet> .Default);
foreach (var extentInfo in extentMap.KeyValuePairs)
{
var principalExtent = extentInfo.Key;
foreach (var fkExtent in GetFKOverPKDependents(principalExtent))
{
// Only track fkExtents that are in extentMap.
ReadOnlyCollection <LeafCellTreeNode> nodes;
if (extentMap.TryGetListForKey(fkExtent, out nodes))
{
// Make sure that we are not adding resultIJDriverChildren as FK dependents - we do not want them to get nested.
if (resultIJDriverChildren == null ||
!resultIJDriverChildren.Contains(nodes.Single()))
{
pkFkMap.Add(principalExtent, fkExtent);
}
}
}
var extentLojNode = new OpCellTreeNode(m_viewgenContext, CellTreeOpType.LOJ);
extentLojNode.Add(extentInfo.Value.Single());
extentLOJs.Add(principalExtent, extentLojNode);
}
// Construct LOJ nesting inside extentLOJs based on the information in pkFkMap.
// Also, track nested extents using nestedExtents.
// Example:
// We start with nestedExtents empty extentLOJs as such:
// tBaseType -> LOJ(BaseTypeNode)
// tDerivedType1 -> LOJ(DerivedType1Node)*
// tDerivedType2 -> LOJ(DerivedType2Node)**
// Note that * and ** represent object references. So each time something is nested,
// we don't clone, but nest the original LOJ. When we get to processing the extent of that LOJ,
// we might add other children to that nested LOJ.
// As we walk pkFkMap, we end up with this:
// tBaseType -> LOJ(BaseTypeNode, LOJ(DerivedType1Node)*, LOJ(DerivedType2Node)**)
// tDerivedType1 -> LOJ(DerivedType1Node)*
// tDerivedType2 -> LOJ(DerivedType2Node)**
// nestedExtens = (tDerivedType1, tDerivedType2)
var nestedExtents = new Dictionary <EntitySet, EntitySet>(EqualityComparer <EntitySet> .Default);
foreach (var m in pkFkMap.KeyValuePairs)
{
var principalExtent = m.Key;
foreach (var fkExtent in m.Value)
{
OpCellTreeNode fkExtentLOJ;
if (extentLOJs.TryGetValue(fkExtent, out fkExtentLOJ)
&&
// make sure we don't nest twice and we don't create a cycle.
!nestedExtents.ContainsKey(fkExtent) &&
!CheckLOJCycle(fkExtent, principalExtent, nestedExtents))
{
extentLOJs[m.Key].Add(fkExtentLOJ);
nestedExtents.Add(fkExtent, principalExtent);
}
}
}
// Now we need to grab the LOJs that have not been nested and add them to the result.
// All LOJs that have been nested must be somewhere inside the LOJs that have not been nested,
// so they as well end up in the result as part of the unnested ones.
foreach (var m in extentLOJs)
{
if (!nestedExtents.ContainsKey(m.Key))
{
// extentLOJ represents (Vx LOJ Vy LOJ(Vm LOJ Vn)) where Vx is the original node from rootNode.Children or resultIJDriverChildren.
var extentLOJ = m.Value;
if (resultIJDriverChildren != null &&
resultIJDriverChildren.Contains(extentLOJ.Children[0]))
{
resultIJDriver.Add(extentLOJ);
}
else
{
result.Add(extentLOJ);
}
}
}
return(result.Flatten());
}
private CellTreeNode ConvertUnionsToNormalizedLOJs(CellTreeNode rootNode)
{
for (int index = 0; index < rootNode.Children.Count; ++index)
{
rootNode.Children[index] = this.ConvertUnionsToNormalizedLOJs(rootNode.Children[index]);
}
if (rootNode.OpType != CellTreeOpType.LOJ || rootNode.Children.Count < 2)
{
return(rootNode);
}
OpCellTreeNode opCellTreeNode1 = new OpCellTreeNode(this.m_viewgenContext, rootNode.OpType);
List <CellTreeNode> cellTreeNodeList = new List <CellTreeNode>();
OpCellTreeNode opCellTreeNode2 = (OpCellTreeNode)null;
HashSet <CellTreeNode> cellTreeNodeSet = (HashSet <CellTreeNode>)null;
if (rootNode.Children[0].OpType == CellTreeOpType.IJ)
{
opCellTreeNode2 = new OpCellTreeNode(this.m_viewgenContext, rootNode.Children[0].OpType);
opCellTreeNode1.Add((CellTreeNode)opCellTreeNode2);
cellTreeNodeList.AddRange((IEnumerable <CellTreeNode>)rootNode.Children[0].Children);
cellTreeNodeSet = new HashSet <CellTreeNode>((IEnumerable <CellTreeNode>)rootNode.Children[0].Children);
}
else
{
opCellTreeNode1.Add(rootNode.Children[0]);
}
foreach (CellTreeNode cellTreeNode in rootNode.Children.Skip <CellTreeNode>(1))
{
OpCellTreeNode opCellTreeNode3 = cellTreeNode as OpCellTreeNode;
if (opCellTreeNode3 != null && opCellTreeNode3.OpType == CellTreeOpType.Union)
{
cellTreeNodeList.AddRange((IEnumerable <CellTreeNode>)opCellTreeNode3.Children);
}
else
{
cellTreeNodeList.Add(cellTreeNode);
}
}
KeyToListMap <EntitySet, LeafCellTreeNode> keyToListMap1 = new KeyToListMap <EntitySet, LeafCellTreeNode>((IEqualityComparer <EntitySet>)EqualityComparer <EntitySet> .Default);
foreach (CellTreeNode child in cellTreeNodeList)
{
LeafCellTreeNode leaf = child as LeafCellTreeNode;
if (leaf != null)
{
EntitySetBase leafNodeTable = (EntitySetBase)BasicViewGenerator.GetLeafNodeTable(leaf);
if (leafNodeTable != null)
{
keyToListMap1.Add((EntitySet)leafNodeTable, leaf);
}
}
else if (cellTreeNodeSet != null && cellTreeNodeSet.Contains(child))
{
opCellTreeNode2.Add(child);
}
else
{
opCellTreeNode1.Add(child);
}
}
foreach (KeyValuePair <EntitySet, List <LeafCellTreeNode> > keyValuePair in keyToListMap1.KeyValuePairs.Where <KeyValuePair <EntitySet, List <LeafCellTreeNode> > >((Func <KeyValuePair <EntitySet, List <LeafCellTreeNode> >, bool>)(m => m.Value.Count > 1)).ToArray <KeyValuePair <EntitySet, List <LeafCellTreeNode> > >())
{
keyToListMap1.RemoveKey(keyValuePair.Key);
foreach (LeafCellTreeNode leafCellTreeNode in keyValuePair.Value)
{
if (cellTreeNodeSet != null && cellTreeNodeSet.Contains((CellTreeNode)leafCellTreeNode))
{
opCellTreeNode2.Add((CellTreeNode)leafCellTreeNode);
}
else
{
opCellTreeNode1.Add((CellTreeNode)leafCellTreeNode);
}
}
}
KeyToListMap <EntitySet, EntitySet> keyToListMap2 = new KeyToListMap <EntitySet, EntitySet>((IEqualityComparer <EntitySet>)EqualityComparer <EntitySet> .Default);
Dictionary <EntitySet, OpCellTreeNode> dictionary = new Dictionary <EntitySet, OpCellTreeNode>((IEqualityComparer <EntitySet>)EqualityComparer <EntitySet> .Default);
foreach (KeyValuePair <EntitySet, List <LeafCellTreeNode> > keyValuePair in keyToListMap1.KeyValuePairs)
{
EntitySet key = keyValuePair.Key;
foreach (EntitySet fkOverPkDependent in BasicViewGenerator.GetFKOverPKDependents(key))
{
ReadOnlyCollection <LeafCellTreeNode> valueCollection;
if (keyToListMap1.TryGetListForKey(fkOverPkDependent, out valueCollection) && (cellTreeNodeSet == null || !cellTreeNodeSet.Contains((CellTreeNode)valueCollection.Single <LeafCellTreeNode>())))
{
keyToListMap2.Add(key, fkOverPkDependent);
}
}
OpCellTreeNode opCellTreeNode3 = new OpCellTreeNode(this.m_viewgenContext, CellTreeOpType.LOJ);
opCellTreeNode3.Add((CellTreeNode)keyValuePair.Value.Single <LeafCellTreeNode>());
dictionary.Add(key, opCellTreeNode3);
}
Dictionary <EntitySet, EntitySet> nestedExtents = new Dictionary <EntitySet, EntitySet>((IEqualityComparer <EntitySet>)EqualityComparer <EntitySet> .Default);
foreach (KeyValuePair <EntitySet, List <EntitySet> > keyValuePair in keyToListMap2.KeyValuePairs)
{
EntitySet key = keyValuePair.Key;
foreach (EntitySet entitySet in keyValuePair.Value)
{
OpCellTreeNode opCellTreeNode3;
if (dictionary.TryGetValue(entitySet, out opCellTreeNode3) && !nestedExtents.ContainsKey(entitySet) && !BasicViewGenerator.CheckLOJCycle(entitySet, key, nestedExtents))
{
dictionary[keyValuePair.Key].Add((CellTreeNode)opCellTreeNode3);
nestedExtents.Add(entitySet, key);
}
}
}
foreach (KeyValuePair <EntitySet, OpCellTreeNode> keyValuePair in dictionary)
{
if (!nestedExtents.ContainsKey(keyValuePair.Key))
{
OpCellTreeNode opCellTreeNode3 = keyValuePair.Value;
if (cellTreeNodeSet != null && cellTreeNodeSet.Contains(opCellTreeNode3.Children[0]))
{
opCellTreeNode2.Add((CellTreeNode)opCellTreeNode3);
}
else
{
opCellTreeNode1.Add((CellTreeNode)opCellTreeNode3);
}
}
}
return(opCellTreeNode1.Flatten());
}