[英]Neo4jClient Union
有谁可以帮助我将此Cypher Query转换为neo4jclient ?
MATCH (o)-[r]-(post:Post)-[:HAS_MentionedUsers]->(assignee1307989068:User),
WHERE (assignee1307989068.UserName = "mhs")
RETURN post,o,r
UNION
MATCH (o)-[r]-(post:Post)-[:HAS_HashTags]-> (Hashtag1841024507:HashTag)
WHERE (Hashtag1841024507.Value = "myTag")
RETURN post,o,r
有任何想法如何基于用户输入在C#和neo4jClient中可能是“ mhs”和“ myTag”的用户动态创建上述密码查询吗?
到目前为止,这是我尝试过的:
search方法将获取搜索词并将其标记化,然后BuildPostQueystring方法将添加密码查询的每个部分。
public Object Search(string searchterm)
{
List<string> where = new List<string>();
var tokenizedstring = searchterm.Split(' ');
var querystring = new StringBuilder();
int unionCount = 0;
var q = new CypherFluentQuery(_graphClient) as ICypherFluentQuery;
foreach (var t in tokenizedstring)
{
_commandService.BuildPostQueystring(t, ref querystring, ref where);
if (querystring[querystring.Length - 1] == ',')
querystring = querystring.Remove(querystring.Length - 1, 1);
if (unionCount > 0)
q = q.Union();
q = q.Match(querystring.ToString());
unionCount++;
int i = 1;
if (where.Count > 0)
q = q.Where(where[0]);
while (i < where.Count)
{
q = q.OrWhere(where[i]);
i++;
}
q = q.Return((post, nodes) => new { Post = post.As<Node<string>>(), Nodes = nodes.As<Node<string>>() })
.OrderBy("post.creationDate");
where.Clear();
querystring.Clear();
}
//var rq = q.Return((post, o) => new {Person = post.As<Node<string>>(), Dog = o.As<Node<string>>()})
// .OrderBy("post.creationDate");
var x = (q as CypherFluentQuery<dynamic>).Results;
return x.ToList();
}
添加查询部分的另一种方法如下:
public void BuildPostQueystring(string token, ref StringBuilder sb, ref List<string> whereConditions)
{
string querystring = "(nodes)-[r]-(post:Post)-[:HAS_{0}]->({1}:{2})";
string wherestring = "({0}.{1} = \"{2}\")";
if (token.StartsWith("#"))
{
int hash = token.GetHashCode();
if (hash < 0)
hash = hash*-1;
string paramName = "Hashtag" + hash;
var str = string.Format(querystring, "HashTags", paramName, "HashTag");
var tvalue = token.Replace("#", "");
//query = query.AndWhere((HashTag hashTag) => hashTag.Value == tvalue);
sb.Append(str);
whereConditions.Add(string.Format(wherestring, paramName, "Value", tvalue));
}
else if (token.StartsWith("+"))
{
int hash = token.GetHashCode();
if (hash < 0)
hash = hash * -1;
string paramName = "team" + hash;
var str = string.Format(querystring, paramName, "MentionedTeam","Team");
sb.Append(str);
var tvalue = token.Replace("+", "");
whereConditions.Add(string.Format(wherestring,paramName, "Name", tvalue));
}
else if (token.StartsWith("@"))
{
int hash = token.GetHashCode();
if (hash < 0)
hash = hash * -1;
string paramName = "assignee" + hash;
var str = string.Format(querystring, "MentionedUsers", paramName, "User");
sb.Append(str);
var tvalue = token.Replace("@", "");
whereConditions.Add(string.Format(wherestring, paramName,"UserName", tvalue));
}
else if (token.StartsWith("by"))
{
int hash = token.GetHashCode();
if (hash < 0)
hash = hash * -1;
string paramName = "author" + hash;
var str = string.Format(querystring, "Author", paramName, "User");
sb.Append(str);
var tvalue = token.Replace("by:", "");
whereConditions.Add(string.Format(wherestring, paramName, "UserName", tvalue));
}
else if (token.Contains("\\"))
{
foreach (var dt in GetLocalDateTokens(_dateTimeTokens))
{
int hash = token.GetHashCode();
if (hash < 0)
hash = hash * -1;
string paramName = "dueDate" + hash;
if (token.ToLower() == dt.Text.ToLower())
{
var neodate = new NeoDateTime();
neodate.Year = dt.GetDate.Year;
neodate.Month = dt.GetDate.Month;
neodate.Day = dt.GetDate.Day;
neodate.TimeStamp = long.Parse(dt.GetDate.ToString("HHmmss"));
neodate.DateStamp = long.Parse(dt.GetDate.ToString("yyyyMMdd"));
neodate.DateTimeStamp = long.Parse(dt.GetDate.ToString("yyyyMMddHHmmss"));
var str = string.Format(querystring, "DueDates", paramName, "NeoDateTim");
sb.Append(str);
var tvalue = token.Replace("by:", "");
whereConditions.Add(string.Format(wherestring, "DateStamp", paramName, tvalue));
}
}
}
else
{
//MATCH (n)
//WHERE n.name =~ 'Tob.*'
//RETURN n
var wherestr = "({0}.{1} =~ '{2}.*')";
//string wherestring = "({0}.{1} = \"{2}\")";
//string querystring = "(post:Post)-[:HAS_{0}]->({1}:{2})";
string paramName = "post" + token + GetHashCode();
string qs = "(post:Post)";
var str = string.Format(qs, paramName);
sb.Append(str);
whereConditions.Add(string.Format(wherestr, "post", "Text", token));
}
if(sb.Length>0)
sb.Append(",");
}
我的第一个问题是如何获取结果,因为q没有结果方法,并且我无法将其转换为匿名类型?
好的,首先, q
没有Results
方法的原因是直到添加Return
调用之前,您只有ICypherFluentQuery
,所以如果您有:
var query = client.Cypher.Match("(n:Post)");
一旦添加Return
语句, query
的类型ICypherFluentQuery
,它没有Results
方法。
var query = client.Cypher.Match("(n:Post)").Return(n => n.As<Post>());
您会发现query
现在是: ICypherFluentQuery<Post>
。 因此,在添加.Return
语句之前,您需要分配给另一个变量:
var query = client.Cypher.Match("(n:Post)");
var retQuery = query.Return(n => n.As<Post>());
var results = retQuery.Results;
第二部分,实际查询。
尚不清楚您要使用代码做什么,但有很多,但是用于查询的代码(在我看来)应该看起来像这样:
private void GetResults(string username, string tagValue)
{
var query = Client.Cypher
.Match("(o)-[r]-(post:Post)-[:HAS_MentionedUsers]->(assignee:User)")
.Where((User assignee) => assignee.UserName == username)
.Return((post, o, r) => new {Post = post.As<Post>(), O = o.As<object>(), R = r.As<RelationshipInstance<object>>()})
.Union()
.Match("(o)-[r]-(post:Post)-[:HAS_MentionedUsers]->(hashTag:HashTag)")
.Where((HashTag hashTag) => hashTag.Value == tagValue)
.Return((post, o, r) => new {Post = post.As<Post>(), O = o.As<object>(), R = r.As<RelationshipInstance<object>>()});
var res = query.Results.ToList();
}
PS:我不知道o
是什么类型,所以我使用object
作为占位符
如果由于某种原因在构建史诗查询时需要使用这些名称assignee1307989068
等,则where
变为:
/* MATCH */
.Where("assignee123.Value == {assignee123Param}")
.WithParam("assignee123", username)
/* RETURN */
如果可以的话,我会选择第一个版本,因为它的类型安全且易于理解。
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