无法将 GraphObject 转换为节点

Question

我将 AbstractQuery 定义为 GraphObject 的 Child :

class AbstractQuery(GraphObject):

    __primarykey__ = "hash"

    hash = Property()
    projname = Property()

    def __init__(self, hash):
        self.hash = hash
        self.projname = ""  # TODO:initialize this

并遍历我（已经存在的）图表中的所有 SQLQuery objects，并希望创建一个由散列组成的新 AbstractQuery。任何 SQLQuery 散列到确定 AbstractQuery 的散列应该被连接：

def addAbstractionLayerSqlQueries(graph, logger=None):
    abstractQueryTable = getAbstractQueries(graph, logger)
    sqlqueries = graph.data("MATCH (n:SQLQuery) return n")

    if logger is not None:
        logger.info("abstracting {} queries".format(len(sqlqueries)))

    counter = 1
    for iterator in sqlqueries:
        query = iterator['n']
        if logger is not None:
            logger.info("abstracting query {}/{}".format(counter,
                                                         len(sqlqueries)))

        hash = sqlNormalizer.generate_normalized_query_hash(query['ts'])

        if hash not in abstractQueryTable:
            abstractQueryNode = al.AbstractQuery(hash)
            abstractQueryTable[hash] = abstractQueryNode
            graph.push(abstractQueryNode)

        rel = Relationship(query, "ABSTRACTSTO", abstractQueryTable[hash])
        graph.create(rel)
        counter = counter + 1

在我开始这个过程之前，我提取了所有已经存在的 AbstractQueries 的 table（使用散列作为键），以防止创建相同的 AbstractQuery 两次。

然而，当我运行方法时，我以异常结束：

TypeError: Cannot cast AbstractQuery to Node

为什么会这样，我该如何解决？

我之前使用此表示法在图表中输入了多个 SQLQueries：

class SQLQuery(GraphObject):

    __primarykey__ = "uuid"

    uuid = Property()

    projname = Property()

    session = Property()
    user = Property()
    seq = Property()
    ts = Property()

    sql = Property()

    Statement = RelatedTo("SQLStatement")
    AbstractsTo = RelatedTo("AbstractQuery")

    def __init__(self, projname=None, session=None, user=None,
                 seq=None, ts=None, sql=None):
        self.projname = projname
        self.session = session
        self.user = user
        self.seq = seq
        self.ts = ts
        self.sql = sql
        self.uuid = "{} [{} {}] {}.{}.{}".format(type(self).__name__,
                                                 seq, ts, projname,
                                                 session, user)

因为我能够使用这种表示来表示和输入节点，所以我很惊讶为什么 py2neo 拒绝我的 AbstractQuery class 作为我的 addAbstractionLayerSqlQueries 函数中的节点。

Answer 1

我通过仅使用对象模型并替换 graph.data(...) 查询部分解决了问题：

def addAbstractionLayerSqlQueries(graph, logger=None):
    abstractQueryTable = getAbstractQueries(graph, logger)
    sqlqueries = list(adlsql.SQLQuery.select(graph))

    print type(sqlqueries)

    if logger is not None:
        logger.info("abstracting {} queries".format(len(sqlqueries)))

    counter = 1
    for query in sqlqueries:
        print type(query)

        if logger is not None:
            logger.info("abstracting query {}/{}".format(counter,
                                                         len(sqlqueries)))

        hash = sqlNormalizer.generate_normalized_query_hash(query.ts)

        if hash not in abstractQueryTable:
            abstractQueryNode = al.AbstractQuery(hash)
            abstractQueryTable[hash] = abstractQueryNode
            graph.push(abstractQueryNode)

        query.AbstractsTo.add(abstractQueryTable[hash])
        graph.push(query)
        counter = counter + 1

但是，错误的真正原因仍然未知，我会接受任何能解释这一点的答案。这个答案只是解决问题。

Answer 2

您正在混合两层 API。 OGM 层位于常规 py2neo API 之上，GraphObject 不直接对应于 Node（它也包含其他内容）。因此，您不能直接从 GraphObject 构建 Relationship。

要访问您GraphObject后面的核心节点，您可以使用my_object.__ogm__.node。

无法将 GraphObject 转换为节点

Cannot cast GraphObject to Node

neo4j

py2neo