/// <summary>
/// Constructs the graph pattern specified by the MATCH clause.
/// The graph pattern may consist of multiple fully-connected sub-graphs.
/// </summary>
/// <param name="query">The SELECT query block</param>
/// <returns>A graph object contains all the connected componeents</returns>
private MatchGraph ConstructGraph(WSelectQueryBlock query)
{
if (query == null || query.MatchClause == null)
return null;
var columnsOfNodeTables = _graphMetaData.ColumnsOfNodeTables;
var nodeViewMapping = _graphMetaData.NodeViewMapping;
var unionFind = new UnionFind();
var edgeColumnToAliasesDict = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
var pathDictionary = new Dictionary<string, MatchPath>(StringComparer.OrdinalIgnoreCase);
var reversedEdgeDict = new Dictionary<string, MatchEdge>();
var matchClause = query.MatchClause;
var nodes = new Dictionary<string, MatchNode>(StringComparer.OrdinalIgnoreCase);
var connectedSubGraphs = new List<ConnectedComponent>();
var subGrpahMap = new Dictionary<string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
var parent = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
unionFind.Parent = parent;
// Constructs the graph pattern specified by the path expressions in the MATCH clause
foreach (var path in matchClause.Paths)
{
var index = 0;
MatchEdge preEdge = null;
for (var count = path.PathEdgeList.Count; index < count; ++index)
{
var currentNodeTableRef = path.PathEdgeList[index].Item1;
var currentEdgeColumnRef = path.PathEdgeList[index].Item2;
var currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
var nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
var nextNodeExposedName = nextNodeTableRef.BaseIdentifier.Value;
var patternNode = nodes.GetOrCreate(currentNodeExposedName);
if (patternNode.NodeAlias == null)
{
patternNode.NodeAlias = currentNodeExposedName;
patternNode.Neighbors = new List<MatchEdge>();
patternNode.External = false;
var nodeTable = _context[currentNodeExposedName] as WNamedTableReference;
if (nodeTable != null)
{
patternNode.NodeTableObjectName = nodeTable.TableObjectName;
if (patternNode.NodeTableObjectName.SchemaIdentifier == null)
patternNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
Identifier edgeIdentifier = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last();
string schema = patternNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
string nodeTableName = patternNode.NodeTableObjectName.BaseIdentifier.Value;
string bindTableName =
_context.EdgeNodeBinding[
new Tuple<string, string>(nodeTableName.ToLower(), edgeIdentifier.Value.ToLower())].ToLower();
var bindNodeTableObjName = new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
);
var edgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(bindNodeTableObjName)][
currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value];
string edgeAlias = currentEdgeColumnRef.Alias;
//string revEdgeAlias = edgeAlias;
bool isReversed = path.IsReversed || edgeColumn.EdgeInfo.IsReversedEdge;
string currentRevEdgeName = null;
// get original edge name
var currentEdgeName = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value;
var originalSourceName = isReversed ?
(_context[nextNodeExposedName] as WNamedTableReference).TableObjectName.BaseIdentifier.Value
: (_context[currentNodeExposedName] as WNamedTableReference).TableObjectName.BaseIdentifier.Value;
if (isReversed)
{
var i = currentEdgeName.IndexOf(originalSourceName, StringComparison.OrdinalIgnoreCase) +
originalSourceName.Length;
currentRevEdgeName = currentEdgeName.Substring(i + 1,
currentEdgeName.Length - "Reversed".Length - i - 1);
}
else
{
var srcTuple = WNamedTableReference.SchemaNameToTuple(patternNode.NodeTableObjectName);
// [nodeView]-[edge]->[node/nodeView]
if (edgeColumn.Role == WNodeTableColumnRole.Edge && nodeViewMapping.ContainsKey(srcTuple))
{
var physicalNodeName =
_context.EdgeNodeBinding[new Tuple<string, string>(srcTuple.Item2, currentEdgeName.ToLower())];
currentRevEdgeName = physicalNodeName + "_" + currentEdgeName + "Reversed";
}
else
{
currentRevEdgeName = originalSourceName + "_" + currentEdgeName + "Reversed";
}
}
if (edgeAlias == null)
{
edgeAlias = !isReversed
? string.Format("{0}_{1}_{2}", currentNodeExposedName, currentEdgeName, nextNodeExposedName)
: string.Format("{0}_{1}_{2}", nextNodeExposedName, currentRevEdgeName, currentNodeExposedName);
//when the current edge is a reversed edge, the key should still be the original edge name
//e.g.: TestDeleteEdgeWithTableAlias
var edgeNameKey = isReversed ? currentRevEdgeName : currentEdgeName;
if (edgeColumnToAliasesDict.ContainsKey(edgeNameKey))
{
edgeColumnToAliasesDict[edgeNameKey].Add(edgeAlias);
}
else
{
edgeColumnToAliasesDict.Add(edgeNameKey, new List<string> { edgeAlias });
}
}
MatchEdge edge, revEdge;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
var isEdgeView = edgeColumn.Role == WNodeTableColumnRole.EdgeView;
var hasRevEdge = edgeColumn.EdgeInfo.HasReversedEdge;
edge = new MatchEdge
{
IsEdgeView = isEdgeView,
IsReversedEdge = false,
HasReversedEdge = hasRevEdge,
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName = bindNodeTableObjName,
};
_context.AddEdgeReference(edge);
if (hasRevEdge)
{
revEdge = new MatchEdge
{
IsEdgeView = isEdgeView,
IsReversedEdge = true,
SinkNode = patternNode,
EdgeColumn = new WEdgeColumnReferenceExpression()
{
ColumnType = currentEdgeColumnRef.ColumnType,
Alias = currentEdgeColumnRef.Alias,
MaxLength = currentEdgeColumnRef.MaxLength,
MinLength = currentEdgeColumnRef.MinLength,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict,
MultiPartIdentifier = new WMultiPartIdentifier(new Identifier()
{
QuoteType = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().QuoteType,
Value = currentRevEdgeName,
}),
},
EdgeAlias = edgeAlias,
//EdgeAlias = revEdgeAlias,
};
reversedEdgeDict[edge.EdgeAlias] = revEdge;
}
}
else
{
MatchPath matchPath = new MatchPath
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict
};
_context.AddEdgeReference(matchPath);
pathDictionary[edgeAlias] = matchPath;
edge = matchPath;
}
if (preEdge != null)
{
preEdge.SinkNode = patternNode;
if (preEdge.HasReversedEdge)
{
//var preSourceNode = preEdge.SourceNode;
var preEdgeBindNodeTableObjName = preEdge.BindNodeTableObjName;
var preEdgeColName = preEdge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value;
var preEdgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(preEdgeBindNodeTableObjName)][
preEdgeColName];
var isEdgeView = preEdgeColumn.Role == WNodeTableColumnRole.EdgeView;
var isNodeView =
_graphMetaData.NodeViewMapping.ContainsKey(
WNamedTableReference.SchemaNameToTuple(patternNode.NodeTableObjectName));
reversedEdgeDict[preEdge.EdgeAlias].SourceNode = patternNode;
// [node/nodeView]-[edgeView]->[node/nodeView]
if (isEdgeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = preEdgeBindNodeTableObjName;
}
// [node/nodeView]-[edge]->[nodeView]
else if (!isEdgeView && isNodeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = "dbo" },
new Identifier { Value = preEdgeColumn.EdgeInfo.SinkNodes.First() }
);
}
else
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = schema },
new Identifier { Value = bindTableName }
);
}
}
}
preEdge = edge;
if (!parent.ContainsKey(currentNodeExposedName))
parent[currentNodeExposedName] = currentNodeExposedName;
if (!parent.ContainsKey(nextNodeExposedName))
parent[nextNodeExposedName] = nextNodeExposedName;
unionFind.Union(currentNodeExposedName, nextNodeExposedName);
patternNode.Neighbors.Add(edge);
}
var tailExposedName = path.Tail.BaseIdentifier.Value;
var tailNode = nodes.GetOrCreate(tailExposedName);
if (tailNode.NodeAlias == null)
{
tailNode.NodeAlias = tailExposedName;
tailNode.Neighbors = new List<MatchEdge>();
var nodeTable = _context[tailExposedName] as WNamedTableReference;
if (nodeTable != null)
{
tailNode.NodeTableObjectName = nodeTable.TableObjectName;
if (tailNode.NodeTableObjectName.SchemaIdentifier == null)
tailNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
if (preEdge != null)
{
preEdge.SinkNode = tailNode;
if (preEdge.HasReversedEdge)
{
var schema = tailNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
var nodeTableName = tailNode.NodeTableObjectName.BaseIdentifier.Value;
//var preSourceNode = preEdge.SourceNode;
var preEdgeBindNodeTableObjName = preEdge.BindNodeTableObjName;
var preEdgeColName = preEdge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value;
var preEdgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(preEdgeBindNodeTableObjName)][
preEdgeColName];
var isEdgeView = preEdgeColumn.Role == WNodeTableColumnRole.EdgeView;
var isNodeView =
_graphMetaData.NodeViewMapping.ContainsKey(
WNamedTableReference.SchemaNameToTuple(tailNode.NodeTableObjectName));
reversedEdgeDict[preEdge.EdgeAlias].SourceNode = tailNode;
// [node/nodeView]-[edgeView]->[node/nodeView]
if (isEdgeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = preEdgeBindNodeTableObjName;
}
// [node/nodeView]-[edge]->[nodeView]
else if (!isEdgeView && isNodeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = "dbo" },
new Identifier { Value = preEdgeColumn.EdgeInfo.SinkNodes.First() }
);
}
else
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = schema },
new Identifier { Value = nodeTableName.ToLower() }
);
}
}
}
}
// Puts nodes into subgraphs
foreach (var node in nodes)
{
string root = unionFind.Find(node.Key);
if (!subGrpahMap.ContainsKey(root))
{
var subGraph = new ConnectedComponent();
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGrpahMap[root] = subGraph;
connectedSubGraphs.Add(subGraph);
subGraph.IsTailNode[node.Value] = false;
}
else
{
var subGraph = subGrpahMap[root];
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGraph.IsTailNode[node.Value] = false;
}
}
var graph = new MatchGraph
{
ReversedEdgeDict = reversedEdgeDict,
ConnectedSubGraphs = connectedSubGraphs,
SourceNodeStatisticsDict = new Dictionary<Tuple<string, bool>, Statistics>(),
};
unionFind.Parent = null;
// When an edge in the MATCH clause is not associated with an alias,
// assigns to it a default alias: sourceAlias_EdgeColumnName_sinkAlias.
// Also rewrites edge attributes anywhere in the query that can be bound to this default alias.
var replaceTableRefVisitor = new ReplaceEdgeReferenceVisitor();
replaceTableRefVisitor.Invoke(query, edgeColumnToAliasesDict);
// Rematerializes node tables in the MATCH clause which are defined in the upper-level context
// and join them with the upper-level table references.
RematerilizeExtrenalNodeTableReference(query, nodes);
// Transforms the path reference in the SELECT elements into a
// scalar function to display path information.
TransformPathInfoDisplaySelectElement(query, pathDictionary);
return graph;
}
// Greate the MatchGraph of this AggregationBlock. If some free nodes and free edges are connected, they are in the same ConnectedComponent
internal HashSet <string> CreateMatchGraph(WMatchClause matchClause)
{
HashSet <string> freeNodesAndEdges = new HashSet <string>();
Dictionary <string, MatchPath> pathCollection = new Dictionary <string, MatchPath>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, MatchNode> nodeCollection = new Dictionary <string, MatchNode>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, MatchEdge> edgeCollection = new Dictionary <string, MatchEdge>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, ConnectedComponent> subgraphCollection = new Dictionary <string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
// we use Disjoint-set data structure to determine whether tables are in the same component or not.
UnionFind unionFind = new UnionFind();
foreach (ConnectedComponent subgraph in this.GraphPattern.ConnectedSubgraphs)
{
foreach (KeyValuePair <string, MatchNode> pair in subgraph.Nodes)
{
nodeCollection.Add(pair.Key, pair.Value);
unionFind.Add(pair.Key);
}
}
if (matchClause != null)
{
foreach (WMatchPath path in matchClause.Paths)
{
int index = 0;
bool outOfBlock = false;
MatchEdge edgeToSrcNode = null;
for (int count = path.PathEdgeList.Count; index < count; ++index)
{
WSchemaObjectName currentNodeTableRef = path.PathEdgeList[index].Item1;
WEdgeColumnReferenceExpression currentEdgeColumnRef = path.PathEdgeList[index].Item2;
WSchemaObjectName nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
string currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
string edgeAlias = currentEdgeColumnRef.Alias;
string nextNodeExposedName = nextNodeTableRef != null ? nextNodeTableRef.BaseIdentifier.Value : null;
// Get the source node of a path
if (!nodeCollection.ContainsKey(currentNodeExposedName))
{
continue;
}
MatchNode srcNode = nodeCollection[currentNodeExposedName];
// Get the edge of a path, and set required attributes
// Because the sourceNode is relative, we need to construct new edges or paths
// But they need to share the same predicates and proerties
MatchEdge edgeFromSrcNode;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
if (!edgeCollection.ContainsKey(edgeAlias))
{
edgeCollection[edgeAlias] = new MatchEdge()
{
LinkAlias = edgeAlias,
SourceNode = srcNode,
EdgeType = currentEdgeColumnRef.EdgeType,
Predicates = new List <WBooleanExpression>(),
BindNodeTableObjName = new WSchemaObjectName(),
IsReversed = false,
Properties = new List <string>(GraphViewReservedProperties.ReservedEdgeProperties)
};
unionFind.Add(edgeAlias);
}
edgeFromSrcNode = new MatchEdge
{
LinkAlias = edgeAlias,
SourceNode = srcNode,
EdgeType = edgeCollection[edgeAlias].EdgeType,
Predicates = edgeCollection[edgeAlias].Predicates,
BindNodeTableObjName = edgeCollection[edgeAlias].BindNodeTableObjName,
IsReversed = false,
Properties = edgeCollection[edgeAlias].Properties
};
}
else
{
if (!pathCollection.ContainsKey(edgeAlias))
{
pathCollection[edgeAlias] = new MatchPath
{
SourceNode = srcNode,
LinkAlias = edgeAlias,
Predicates = new List <WBooleanExpression>(),
BindNodeTableObjName = new WSchemaObjectName(),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict,
IsReversed = false,
EdgeType = currentEdgeColumnRef.EdgeType,
Properties = new List <string>(GraphViewReservedProperties.ReservedEdgeProperties)
};
}
edgeFromSrcNode = new MatchPath
{
SourceNode = srcNode,
LinkAlias = edgeAlias,
Predicates = pathCollection[edgeAlias].Predicates,
BindNodeTableObjName = pathCollection[edgeAlias].BindNodeTableObjName,
MinLength = pathCollection[edgeAlias].MinLength,
MaxLength = pathCollection[edgeAlias].MaxLength,
ReferencePathInfo = false,
AttributeValueDict = pathCollection[edgeAlias].AttributeValueDict,
IsReversed = false,
EdgeType = pathCollection[edgeAlias].EdgeType,
Properties = pathCollection[edgeAlias].Properties
};
}
if (path.IsReversed)
{
unionFind.Union(edgeAlias, currentNodeExposedName);
}
else
{
unionFind.Union(currentNodeExposedName, edgeAlias);
}
if (edgeToSrcNode != null)
{
edgeToSrcNode.SinkNode = srcNode;
if (!(edgeToSrcNode is MatchPath))
{
// Construct reverse edge
MatchEdge reverseEdge = new MatchEdge
{
SourceNode = edgeToSrcNode.SinkNode,
SinkNode = edgeToSrcNode.SourceNode,
LinkAlias = edgeToSrcNode.LinkAlias,
Predicates = edgeToSrcNode.Predicates,
BindNodeTableObjName = edgeToSrcNode.BindNodeTableObjName,
IsReversed = true,
EdgeType = edgeToSrcNode.EdgeType,
Properties = edgeToSrcNode.Properties,
};
srcNode.ReverseNeighbors.Add(reverseEdge);
}
}
edgeToSrcNode = edgeFromSrcNode;
// Add this edge to node's neightbors
if (nextNodeExposedName != null)
{
if (path.IsReversed)
{
unionFind.Union(nextNodeExposedName, edgeAlias);
}
else
{
unionFind.Union(edgeAlias, nextNodeExposedName);
}
srcNode.Neighbors.Add(edgeFromSrcNode);
}
// Add this edge to node's dangling edges
else
{
srcNode.DanglingEdges.Add(edgeFromSrcNode);
}
}
if (path.Tail == null)
{
continue;
}
// Get destination node of a path
string tailExposedName = path.Tail.BaseIdentifier.Value;
if (!nodeCollection.ContainsKey(tailExposedName))
{
continue;
}
MatchNode destNode = nodeCollection[tailExposedName];
if (edgeToSrcNode != null)
{
edgeToSrcNode.SinkNode = destNode;
if (!(edgeToSrcNode is MatchPath))
{
// Construct reverse edge
MatchEdge reverseEdge = new MatchEdge
{
SourceNode = edgeToSrcNode.SinkNode,
SinkNode = edgeToSrcNode.SourceNode,
LinkAlias = edgeToSrcNode.LinkAlias,
Predicates = edgeToSrcNode.Predicates,
BindNodeTableObjName = edgeToSrcNode.BindNodeTableObjName,
IsReversed = true,
EdgeType = edgeToSrcNode.EdgeType,
Properties = edgeToSrcNode.Properties,
};
destNode.ReverseNeighbors.Add(reverseEdge);
}
}
}
}
// Use union find algorithmn to define which subgraph does a node belong to and put it into where it belongs to.
foreach (var node in nodeCollection)
{
freeNodesAndEdges.Add(node.Key);
string root = unionFind.Find(node.Key);
ConnectedComponent subGraph;
if (!subgraphCollection.ContainsKey(root))
{
subGraph = new ConnectedComponent();
subgraphCollection[root] = subGraph;
}
else
{
subGraph = subgraphCollection[root];
}
subGraph.Nodes[node.Key] = node.Value;
subGraph.IsTailNode[node.Value] = false;
foreach (MatchEdge edge in node.Value.Neighbors)
{
subGraph.Edges[edge.LinkAlias] = edge;
freeNodesAndEdges.Add(edge.LinkAlias);
}
foreach (MatchEdge edge in node.Value.DanglingEdges)
{
subGraph.Edges[edge.LinkAlias] = edge;
edge.IsDanglingEdge = true;
freeNodesAndEdges.Add(edge.LinkAlias);
}
if (node.Value.Neighbors.Count + node.Value.ReverseNeighbors.Count + node.Value.DanglingEdges.Count > 0)
{
node.Value.Properties.Add(GremlinKeyword.Star);
}
}
this.GraphPattern = new MatchGraph(subgraphCollection.Values.ToList());
return(freeNodesAndEdges);
}
/// <summary>
/// Constructs the graph pattern specified by the MATCH clause.
/// The graph pattern may consist of multiple fully-connected sub-graphs.
/// </summary>
/// <param name="query">The SELECT query block</param>
/// <returns>A graph object contains all the connected componeents</returns>
private MatchGraph ConstructGraph(WSelectQueryBlock query)
{
if (query == null || query.MatchClause == null)
return null;
var unionFind = new UnionFind();
var edgeColumnToAliasesDict = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
var pathDictionary = new Dictionary<string, MatchPath>(StringComparer.OrdinalIgnoreCase);
var matchClause = query.MatchClause;
var nodes = new Dictionary<string, MatchNode>(StringComparer.OrdinalIgnoreCase);
var connectedSubGraphs = new List<ConnectedComponent>();
var subGrpahMap = new Dictionary<string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
var parent = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
unionFind.Parent = parent;
// Constructs the graph pattern specified by the path expressions in the MATCH clause
foreach (var path in matchClause.Paths)
{
var index = 0;
MatchEdge preEdge = null;
for (var count = path.PathEdgeList.Count; index < count; ++index)
{
var currentNodeTableRef = path.PathEdgeList[index].Item1;
var currentEdgeColumnRef = path.PathEdgeList[index].Item2;
var currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
var nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
var nextNodeExposedName = nextNodeTableRef.BaseIdentifier.Value;
var patternNode = nodes.GetOrCreate(currentNodeExposedName);
if (patternNode.NodeAlias == null)
{
patternNode.NodeAlias = currentNodeExposedName;
patternNode.Neighbors = new List<MatchEdge>();
patternNode.External = false;
var nodeTable = _context[currentNodeExposedName] as WNamedTableReference;
if (nodeTable != null)
{
patternNode.NodeTableObjectName = nodeTable.TableObjectName;
if (patternNode.NodeTableObjectName.SchemaIdentifier == null)
patternNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
string edgeAlias = currentEdgeColumnRef.Alias;
if (edgeAlias == null)
{
var currentEdgeName = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value;
edgeAlias = string.Format("{0}_{1}_{2}", currentNodeExposedName, currentEdgeName,
nextNodeExposedName);
if (edgeColumnToAliasesDict.ContainsKey(currentEdgeName))
{
edgeColumnToAliasesDict[currentEdgeName].Add(edgeAlias);
}
else
{
edgeColumnToAliasesDict.Add(currentEdgeName, new List<string> { edgeAlias });
}
}
Identifier edgeIdentifier = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last();
string schema = patternNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
string nodeTableName = patternNode.NodeTableObjectName.BaseIdentifier.Value;
string bindTableName =
_context.EdgeNodeBinding[
new Tuple<string, string>(nodeTableName.ToLower(), edgeIdentifier.Value.ToLower())].ToLower();
MatchEdge edge;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
edge = new MatchEdge
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
};
_context.AddEdgeReference(edge);
}
else
{
MatchPath matchPath = new MatchPath
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict
};
_context.AddEdgeReference(matchPath);
pathDictionary[edgeAlias] = matchPath;
edge = matchPath;
}
if (preEdge != null)
{
preEdge.SinkNode = patternNode;
}
preEdge = edge;
if (!parent.ContainsKey(currentNodeExposedName))
parent[currentNodeExposedName] = currentNodeExposedName;
if (!parent.ContainsKey(nextNodeExposedName))
parent[nextNodeExposedName] = nextNodeExposedName;
unionFind.Union(currentNodeExposedName, nextNodeExposedName);
patternNode.Neighbors.Add(edge);
}
var tailExposedName = path.Tail.BaseIdentifier.Value;
var tailNode = nodes.GetOrCreate(tailExposedName);
if (tailNode.NodeAlias == null)
{
tailNode.NodeAlias = tailExposedName;
tailNode.Neighbors = new List<MatchEdge>();
var nodeTable = _context[tailExposedName] as WNamedTableReference;
if (nodeTable != null)
{
tailNode.NodeTableObjectName = nodeTable.TableObjectName;
if (tailNode.NodeTableObjectName.SchemaIdentifier == null)
tailNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
if (preEdge != null)
preEdge.SinkNode = tailNode;
}
// Puts nodes into subgraphs
foreach (var node in nodes)
{
string root = unionFind.Find(node.Key);
if (!subGrpahMap.ContainsKey(root))
{
var subGraph = new ConnectedComponent();
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGrpahMap[root] = subGraph;
connectedSubGraphs.Add(subGraph);
subGraph.IsTailNode[node.Value] = false;
}
else
{
var subGraph = subGrpahMap[root];
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGraph.IsTailNode[node.Value] = false;
}
}
var graph = new MatchGraph
{
ConnectedSubGraphs = connectedSubGraphs,
};
unionFind.Parent = null;
// When an edge in the MATCH clause is not associated with an alias,
// assigns to it a default alias: sourceAlias_EdgeColumnName_sinkAlias.
// Also rewrites edge attributes anywhere in the query that can be bound to this default alias.
var replaceTableRefVisitor = new ReplaceEdgeReferenceVisitor();
replaceTableRefVisitor.Invoke(query, edgeColumnToAliasesDict);
// Rematerializes node tables in the MATCH clause which are defined in the upper-level context
// and join them with the upper-level table references.
RematerilizeExtrenalNodeTableReference(query, nodes);
// Transforms the path reference in the SELECT elements into a
// scalar function to display path information.
TransformPathInfoDisplaySelectElement(query, pathDictionary);
return graph;
}