是否有(大致)SQL或类似xquery的语言来查询JSON?

我正在考虑非常小的数据集,很好地映射到JSON,它将很容易回答查询,如“X的所有值是什么,Y > 3”或做通常的SUM / COUNT类型操作。

作为一个完全虚构的例子,是这样的:

[{"x": 2, "y": 0}}, {"x": 3, "y": 1}, {"x": 4, "y": 1}]

SUM(X) WHERE Y > 0     (would equate to 7)
LIST(X) WHERE Y > 0    (would equate to [3,4])

我认为这将在客户端和服务器端工作,结果将被转换为适当的特定于语言的数据结构(或者可能保留为JSON)

快速搜索一下谷歌,就会发现人们已经考虑过它并实现了一些东西(JAQL),但它似乎还没有一个标准的用法或库集出现。虽然单独实现每个功能都是相当琐碎的,但如果有人已经做对了,我就不想重新发明轮子。

有什么建议吗?

Edit: This may indeed be a bad idea or JSON may be too generic a format for what I'm thinking.. The reason for wanting a query language instead of just doing the summing/etc functions directly as needed is that I hope to build the queries dynamically based on user-input. Kinda like the argument that "we don't need SQL, we can just write the functions we need". Eventually that either gets out of hand or you end up writing your own version of SQL as you push it further and further. (Okay, I know that is a bit of a silly argument, but you get the idea..)


当前回答

当前的Jaql实现目标是使用Hadoop集群进行大型数据处理,因此可能超出了您的需求。然而,它可以在没有Hadoop集群的情况下轻松运行(但仍然需要编译Hadoop代码及其依赖项,其中大部分都包括在内)。Jaql的一个小实现可以嵌入到Javascript和浏览器中,这将是对项目的一个很好的补充。

上面的例子很容易用jaql编写:

$data = [{"x": 2, "y": 0}, {"x": 3, "y": 1}, {"x": 4, "y": 1}];

$data -> filter $.y > 0 -> transform $.x -> sum(); // 7

$data -> filter $.y > 0 -> transform $.x; // [3,4]

当然,还有更多。例如:

// Compute multiple aggregates and change nesting structure:
$data -> group by $y = $.y into { $y, s:sum($[*].x), n:count($), xs:$[*].x}; 
    // [{ "y": 0, "s": 2, "n": 1, "xs": [2]   },
    //  { "y": 1, "s": 7, "n": 2, "xs": [3,4] }]

// Join multiple data sets:
$more = [{ "y": 0, "z": 5 }, { "y": 1, "z": 6 }];
join $data, $more where $data.y == $more.y into {$data, $more};
    // [{ "data": { "x": 2, "y": 0 }, "more": { "y": 0, "z": 5 }},
    //  { "data": { "x": 3, "y": 1 }, "more": { "y": 1, "z": 6 }},
    //  { "data": { "x": 4, "y": 1 }, "more": { "y": 1, "z": 6 }}]

Jaql可以在http://code.google.com/p/jaql/上下载和讨论

其他回答

另一种方法是使用mongoDB,你可以将JSON存储在mongoDB中,然后通过mongoDB查询语法进行查询。

更新:XQuery 3.1可以查询XML或JSON—或者同时查询两者。XPath 3.1也可以。

这个名单还在增加:

JSONiq(基于XQuery) UNQL(类似SQL) JaQL(功能) JsonPath(于xpath) Json查询(类似于xpath) GraphQL(基于模板,类型化)

你可以使用linq.js。

这允许从对象的数据集中使用聚合和选择,就像其他结构数据一样。

var data = [{x: 2, y: 0}, {x: 3 y: 1}, {x: 4, y: 1}); // sum (x) where y > 0 -> console.log (Enumerable.From(数据)其中(" $。y > 0").Sum("$.x")); // list (x) where y > 0 -> [3,4] console.log (Enumerable.From(数据)其中(" $。y > 0").Select("$.x").ToArray()); < script src = " https://cdnjs.cloudflare.com/ajax/libs/linq.js/2.2.0.2/linq.js " > < /脚本>

下面是一些简单的javascript库,也可以做到这一点:

Dollar Q is a nice lightweight library. It has a familiar feel to the chaining syntax made popular by jQuery and is only 373 SLOC. SpahQL is a fully featured query language with a syntax similar to XPath (Homepage, Github jFunk is an in progress query language, with a syntax similar to CSS/jQuery selectors. It looked promising, but hasn't had any development beyond its in initial commit. (added 2014): the jq command line tool has a neat syntax, but unfortunately it is a c library. Example usage: < package.json jq '.dependencies | to_entries | .[] | select(.value | startswith("git")) | .key'

如果你想使用纯javascript试试这个:

Var对象= {result: {data: {point1: "x", value: 2}, foo: {bar: 7}}}, Path = 'result.data.value', getValue = (o, p) => p.split('.')。Reduce ((r, k) => r[k], o); console.log (getValue(对象,路径));