如何在mongodb中搜索逗号分隔的数据 [英] How to search comma separated data in mongodb

问题描述

我有不同字段的电影数据库.类型字段包含逗号分隔的字符串，例如:

I have movie database with different fields. the Genre field contains a comma separated string like :

{genre: 'Action, Adventure, Sci-Fi'}

我知道我可以使用正则表达式来查找匹配项.我也尝试过:

I know I can use regular expression to find the matches. I also tried:

{'genre': {'$in': genre}}

问题是运行时间.返回查询结果需要花费大量时间.数据库中大约有30万个文档，我已经对体裁"字段进行了正常索引.

the problem is the running time. it take lot of time to return a query result. the database has about 300K documents and I have done normal indexing over 'genre' field.

推荐答案

会说使用

Would say use Map-Reduce to create a separate collection that stores the genre as an array with values coming from the split comma separated string, which you can then run the Map-Reduce job and administer queries on the output collection.

例如，我已经为foo集合创建了一些示例文档:

For example, I've created some sample documents to the foo collection:

db.foo.insert([
    {genre: 'Action, Adventure, Sci-Fi'},
    {genre: 'Thriller, Romantic'},
    {genre: 'Comedy, Action'}
])

然后，下面的map/reduce操作将产生一个集合，您可以从中应用性能查询:

The following map/reduce operation will then produce the collection from which you can apply performant queries:

map = function() {
    var array = this.genre.split(/\s*,\s*/);
    emit(this._id, array);
}

reduce = function(key, values) {
    return values;
}

result = db.runCommand({
    "mapreduce" : "foo", 
    "map" : map,
    "reduce" : reduce,
    "out" : "foo_result"
});

查询将非常简单，将查询与value字段上的多键索引结合使用:

Querying would be straightforward, leveraging the queries with an multi-key index on the value field:

db.foo_result.createIndex({"value": 1});

var genre = ['Action', 'Adventure'];
db.foo_result.find({'value': {'$in': genre}})

输出:

/* 0 */
{
    "_id" : ObjectId("55842af93cab061ff5c618ce"),
    "value" : [ 
        "Action", 
        "Adventure", 
        "Sci-Fi"
    ]
}

/* 1 */
{
    "_id" : ObjectId("55842af93cab061ff5c618d0"),
    "value" : [ 
        "Comedy", 
        "Action"
    ]
}

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