public override Dictionary <OGM, CollectionItemList> Load(IEnumerable <OGM> parents, Core.EntityCollectionBase target)
{
if (parents.Count() == 0)
{
return(new Dictionary <OGM, CollectionItemList>());
}
Dictionary <object, OGM> parentDict = new Dictionary <object, OGM>();
foreach (OGM parent in parents)
{
object?key = parent.GetKey();
if (key is null)
{
continue;
}
if (!parentDict.ContainsKey(key))
{
parentDict.Add(key, parent);
}
}
string matchClause = string.Empty;
if (target.Direction == DirectionEnum.In)
{
matchClause = "MATCH ({0})-[rel:{2}]->({3})";
}
else if (target.Direction == DirectionEnum.Out)
{
matchClause = "MATCH ({0})<-[rel:{2}]-({3})";
}
string whereClause = " WHERE node.{1} in ({{keys}}) ";
string returnClause = " RETURN node.{1} as ParentKey, out.{4} as ItemKey ";
if (target.Relationship.IsTimeDependent)
{
returnClause = $" RETURN node.{{1}} as ParentKey, out.{{4}} as ItemKey, rel.{target.Relationship.StartDate} as StartDate, rel.{target.Relationship.EndDate} as EndDate";
}
Entity targetEntity = target.ForeignEntity;
string[] nodeNames = target.Parent.GetEntity().GetDbNames("node");
string[] outNames = targetEntity.GetDbNames("out");
if (nodeNames.Length > 1 && outNames.Length > 1)
{
throw new InvalidOperationException("Both ends are virtual entities, this is too expensive to query...");
}
List <string> fullMatch = new List <string>();
for (int nodeIndex = 0; nodeIndex < nodeNames.Length; nodeIndex++)
{
for (int outIndex = 0; outIndex < outNames.Length; outIndex++)
{
string match = string.Format(string.Concat(matchClause, whereClause, returnClause),
nodeNames[nodeIndex],
target.ParentEntity.Key.Name,
target.Relationship.Neo4JRelationshipType,
outNames[outIndex],
targetEntity.Key.Name);
fullMatch.Add(match);
}
}
Dictionary <string, object?> parameters = new Dictionary <string, object?>();
parameters.Add("keys", parents.Select(item => item.GetKey()).ToArray());
if (parents.Any(parent => parent.GetEntity() != target.Parent.GetEntity()))
{
throw new InvalidOperationException("This code should only load collections of the same concrete parent class.");
}
var result = Transaction.RunningTransaction.Run(string.Join(" UNION ", fullMatch), parameters);
List <RelationshipIndex> indexCache = new List <RelationshipIndex>();
foreach (var record in result)
{
DateTime?startDate = null;
DateTime?endDate = null;
if (target.Relationship.IsTimeDependent)
{
startDate = (record.Values["StartDate"] != null) ? Conversion <long, DateTime> .Convert((long)record.Values["StartDate"].As <long>()) : (DateTime?)null;
endDate = (record.Values["EndDate"] != null) ? Conversion <long, DateTime> .Convert((long)record.Values["EndDate"].As <long>()) : (DateTime?)null;
}
indexCache.Add(new RelationshipIndex(record.Values["ParentKey"].As <object>(), record.Values["ItemKey"].As <object>(), startDate, endDate));
}
Dictionary <object, List <RawNode> > itemsCache = Load(targetEntity, indexCache.Select(r => r.TargetEntityKey));
List <CollectionItem> items = new List <CollectionItem>();
foreach (var index in indexCache)
{
OGM parent = parentDict[index.SourceEntityKey];
foreach (var item in itemsCache[index.TargetEntityKey])
{
OGM?child = ReadNode(parent, targetEntity, item);
items.Add(target.NewCollectionItem(parent, child, index.StartDate, index.EndDate));
}
}
return(CollectionItemList.Get(items));
}
public override Dictionary <OGM, CollectionItemList> Load(IEnumerable <OGM> parents, Core.EntityCollectionBase target)
{
if (parents.Count() == 0)
{
return(new Dictionary <OGM, CollectionItemList>());
}
HashSet <OGM> parentHashset = new HashSet <OGM>(parents);
string matchClause = string.Empty;
if (target.Direction == DirectionEnum.In)
{
matchClause = "MATCH ({0})-[rel:{2}]->({3})";
}
else if (target.Direction == DirectionEnum.Out)
{
matchClause = "MATCH ({0})<-[rel:{2}]-({3})";
}
string whereClause = " WHERE node.{1} in ($keys) ";
string returnClause = " RETURN node as Parent, out as Item ";
if (target.Relationship.IsTimeDependent)
{
returnClause = $" RETURN node as Parent, out as Item, rel.{target.Relationship.StartDate} as StartDate, rel.{target.Relationship.EndDate} as EndDate";
}
Entity targetEntity = target.ForeignEntity;
string[] nodeNames = target.Parent.GetEntity().GetDbNames("node");
string[] outNames = targetEntity.GetDbNames("out");
if (nodeNames.Length > 1 && outNames.Length > 1)
{
throw new InvalidOperationException("Both ends are virtual entities, this is too expensive to query...");
}
List <string> fullMatch = new List <string>();
for (int nodeIndex = 0; nodeIndex < nodeNames.Length; nodeIndex++)
{
for (int outIndex = 0; outIndex < outNames.Length; outIndex++)
{
string match = string.Format(string.Concat(matchClause, whereClause, returnClause),
nodeNames[nodeIndex],
target.ParentEntity.Key.Name,
target.Relationship.Neo4JRelationshipType,
outNames[outIndex]);
fullMatch.Add(match);
}
}
Dictionary <string, object?> parameters = new Dictionary <string, object?>();
parameters.Add("keys", parents.Select(item => item.GetKey()).ToArray());
if (parents.Any(parent => parent.GetEntity() != target.Parent.GetEntity()))
{
throw new InvalidOperationException("This code should only load collections of the same concrete parent class.");
}
string cypher = string.Join(" UNION ", fullMatch);
var result = Transaction.RunningTransaction.Run(cypher, parameters);
List <CollectionItem> items = new List <CollectionItem>();
foreach (var record in result)
{
DateTime?startDate = null;
DateTime?endDate = null;
if (target.Relationship.IsTimeDependent)
{
startDate = (record.Values["StartDate"] is not null) ? Conversion <long, DateTime> .Convert((long)record.Values["StartDate"].As <long>()) : (DateTime?)null;
endDate = (record.Values["EndDate"] is not null) ? Conversion <long, DateTime> .Convert((long)record.Values["EndDate"].As <long>()) : (DateTime?)null;
}
OGM?parent = target.Parent.GetEntity().Map(record.Values["Parent"].As <RawNode>(), NodeMapping.AsWritableEntity);
OGM?item = targetEntity.Map(record.Values["Item"].As <RawNode>(), NodeMapping.AsWritableEntity);
if (parent is null || item is null)
{
throw new NotSupportedException("The cypher query expected to have a parent node and a child node.");
}
if (parentHashset.Contains(parent))
{
items.Add(target.NewCollectionItem(parent, item, startDate, endDate));
}
}
return(CollectionItemList.Get(items));
}