Question

我的mongodb找到代码：

db.mycollection.runCommand( "text", { search: "yardim", limit:5})

聚合命令：

db.mycollection.aggregate(
{$match:{"source" : {$exists:true}}},
{$group:{_id:"$source", "count": {$sum:1}}} 
);

如何将“聚合”代码集成到“查找”代码

Answer 1

MongoDB的一个乐趣就是它与你的编程语言配合得很好！因此，我鼓励您记住并（重新）将您的编程语言视为实施解决方案的主要工具。我轻轻地建议你做“明显的”，收集你的数据库操作的结果，并插入你想要的。这应该是您的第一个解决方案。希望它能为您带来足够好的表现，因为它也是目前唯一的解决方案（好吧，mapReduce可以合并，但它会强制将其结果的形状合并到合并中）。用于聚合的$ out运算符（从版本2.5.2开始提供）不是合并的解决方案。在将结果写入值指定的集合时，您无法合并回同一个集合。如果集合已存在，则旧的现有集合将替换为集合的新结果。

这是一个示例，希望能够很好地说明使用编程语言解决问题的难易程度。

聚集物insert.js

db.mycollection.drop();
db.mycollection.ensureIndex({ quote: "text", source: "text" });
var docs = [
    {quote: "Glory is fleeting, but obscurity is forever.", source: "Napoleon Bonaparte"},
    {quote: "Political correctness is tyranny with manners.", source: "Charlton Heston"},
    {quote: "Not everything that can be counted counts, and not everything that counts can be counted.", source: "Albert Einstein"},
    {quote: "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.", source: "Albert Einstein"},
    {quote: "In theory, there is no difference between theory and practice. But in practice, there is.", source: "Yogi Berra"},
    {quote: "I find that the harder I work, the more luck I seem to have.", source: "Thomas Jefferson"},
    {quote: "Never interrupt your enemy when he is making a mistake.", source: "Napoleon Bonaparte"},
    {quote: "The significant problems we face cannot be solved at the same level of thinking we were at when we created them.", source: "Albert Einstein"},
];
db.mycollection.insert(docs);
var aggregation = db.mycollection.aggregate(
    {$match: {source: {$exists: true}}},
    {$group: {_id: "$source", count: {$sum: 1}}},
    {$project: {_id: 0, source: "$_id", count: "$count"}}
);
db.mycollection.insert(aggregation.toArray());
var text_search = db.mycollection.runCommand( "text", { search: "Thomas", limit:5});
printjson(text_search.results);

$ mongo aggregate-insert.js

MongoDB shell version: 2.5.4-pre-
connecting to: test
[
    {
        "score" : 0.75,
        "obj" : {
            "_id" : ObjectId("528e3250ac6deb4e169c900e"),
            "quote" : "I find that the harder I work, the more luck I seem to have.",
            "source" : "Thomas Jefferson"
        }
    },
    {
        "score" : 0.75,
        "obj" : {
            "_id" : ObjectId("528e32504294d7fa2eedec1d"),
            "count" : 1,
            "source" : "Thomas Jefferson"
        }
    }
]

mongodb add aggregate命令用来查找命令

1 个答案: