索引neo4j中的现有关系 [英] Index existing relationships in neo4j

问题描述

是否可以在现有关系上添加索引. 更具体地说，我有一个名为Relatadness的关系，它具有一个名为score(得分为double)的属性，我想对其进行索引(使用Java或通过Web客户端). 那怎么办 预先感谢

Is it possible to add index on existing relationships. More specifically I have a relationship called Relatadness with one property called score(score is double) and I want to index it (with java or through the web client). How can do that? thanks in advance

推荐答案

由于已经具有关系，因此必须遍历所有关系.此代码示例将创建一个名为RelatadnessIndex的索引，并将关系存储在score键下的索引中:

Since you already have the relationships, you'll have to iterate through all of them. This code example will create an index called RelatadnessIndex, and store the relationship in the index under a key of score:

    GlobalGraphOperations ggo = GlobalGraphOperations.at(db);
    Index<Relationship> relatadnessIndex = db.index().forRelationships("RelatadnessIndex");
    for (Relationship r : ggo.getAllRelationships()) {
        if (r.getType().name().equals("Relatadness")) {
            double score = (double) r.getProperty("score");
            relatadnessIndex.add(r, "score", score);
        }
    }

请注意，默认情况下，Neo4j/Lucene会将值索引为字符串，因此无法进行数字范围搜索.如果要将其存储为数字，则需要更改以添加为:

Note that by default Neo4j/Lucene will index the value as a String, so doing numeric range searches won't work. If you want to have it stored as a Numeric, you'll need to change to add to be this:

relatadnessIndex.add(r, "score", new ValueContext( score ).indexNumeric() );

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