MongoDB 查询和修改命令

一、MongoDB Insert 命令

Insert 命令 在集合中插入一个或多个文档，并返回一个包含所有输入状态的文档。insert 方法内部使用了 MongoDB 提供的 insert 命令。

语法：

{  
   insert: <collection>,  
   documents: [ <document>, <document>, <document>, ... ],  
   ordered: <boolean>,  
   writeConcern: { <write concern> },  
   bypassDocumentValidation: <boolean>  
}  

参数字段：

示例：

让我们在 books 集合中插入一个文档：

db.runCommand(  
   {  
      insert: "books",  
      documents: [ { _id: 1, bookname: "MongoDB", status: "sold" } ]  
   }  
)  

二、MongoDB Delete 命令

我们可以使用 delete 命令从集合中删除任何文档。单个删除命令中有多个删除规范。我们不能在有上限的集合上使用它。delete 命令在内部由 MongoDB 提供的删除方法使用。

语法：

{  
   delete: <collection>,  
   deletes: [  
      { q : <query>, limit : <integer>, collation: <document> },  
      { q : <query>, limit : <integer>, collation: <document> },  
      { q : <query>, limit : <integer>, collation: <document> },  
      ...  
   ],  
   ordered: <boolean>,  
   writeConcern: { <write concern> }  
}  

参数字段：

collation: {
   locale: <string>,
   caseLevel: <boolean>,
   caseFirst: <string>,
   strength: <int>,
   numericOrdering: <boolean>,
   alternate: <string>,
   maxVariable: <string>,
   backwards: <boolean>
}

示例：

以下示例通过指定限制 2 从图书集合中删除状态等于 A 的文档。

db.runCommand(  
   {  
      delete: "books",  
      deletes: [ { q: { status: "A" }, limit: 1 } ]  
   }  
)  

三、MongoDB Update 命令

update 命令对集合中的文档进行更改。它包含多个更新语句。它由 MongoDB 驱动程序提供的更新方法使用。

语法：

db.runCommand(  
   {  
      update: <collection>,  
      updates: [  
         {  
           q: <query>,  
           u: <document or pipeline>,      // Changed in MongoDB 4.2,  
           upsert: <boolean>,  
           multi: <boolean>,  
           collation: <document>,  
           arrayFilters: <array>,  
           hint: <document|string>        // Available starting in MongoDB 4.2  
         },  
         ...  
      ],  
      ordered: <boolean>,  
      writeConcern: { <write concern> },  
      bypassDocumentValidation: <boolean>  
   }  
)  

参数字段：

collation: {
   locale: <string>,
   caseLevel: <boolean>,
   caseFirst: <string>,
   strength: <int>,
   numericOrdering: <boolean>,
   alternate: <string>,
   maxVariable: <string>,
   backwards: <boolean>
}

示例：

让我们创建一个学生的Collection：

Db.students.insertMany([  
   { _id: 1, student: "john", status: "Pending", points: 0, misc1: "note to self: confirm status", misc2: "Need to activate" },  
   { _id: 2, student: "Michael", status: "D", points: 59, misc1: "reminder: ping me at 100pts", misc2: "Some random comment" },  
]) 

run 命令使用 $set 和 $inc 运算符来更新成员等于“john”的文档的状态。

db.runCommand(  
   {  
      update: "students",  
      updates: [  
         {  
           q: { student: "john" }, u: { $set: { status: "A" }, $inc: { points: 1 } }  
         }  
      ],  
      ordered: false,  
      writeConcern: { w: "majority", wtimeout: 5000 }  
   }  
)  

四、MongoDB find 命令

find 命令用于执行查询并返回第一组结果和游标的 id，我们可以从中构造游标。

语法：

db.runCommand(  
  
   {  
      "find": <string>,  
      "filter": <document>,  
      "sort": <document>,  
      "projection": <document>,  
      "hint": <document or string>,  
      "skip": <int>,  
      "limit": <int>,  
      "batchSize": <int>,  
      "singleBatch": <bool>,  
      "comment": <string>,  
      "maxTimeMS": <int>,  
      "readConcern": <document>,  
      "max": <document>,  
      "min": <document>,  
      "returnKey": <bool>,  
      "showRecordId": <bool>,  
      "tailable": <bool>,  
      "oplogReplay": <bool>,  
      "noCursorTimeout": <bool>,  
      "awaitData": <bool>,  
      "allowPartialResults": <bool>,  
      "collation": <document>  
   }  
)

参数字段：

ReadConcern: { level: <value> }

{ find: "data", oplogReplay: true, filter: 
		{ ts: { $gte: new Timestamp(1514764800, 0) } } }

collation: {
   locale: <string>,
   caseLevel: <boolean>,
   caseFirst: <string>,
   strength: <int>,
   numericOrdering: <boolean>,
   alternate: <string>,
   maxVariable: <string>,
   backwards: <boolean>
}

示例：

在下面的示例中，该命令按名称字段对结果集中的文档进行排序，并将结果集限制为六个文档。

db.runCommand(  
   {  
     find: "restaurants",  
     filter: { rating: { $gte: 9 }, cuisine: "American" },  
     projection: { name: 1, rating: 1, address: 1 },  
     sort: { name: 1 },  
     limit: 6  
   }  
)  

五、MongoDB findAndModify 命令

findAndModify  命令一次修改并返回一个文档。返回的文档默认不包含对更新所做的修改。我们需要使用新选项来返回修改后的文档。

语法：

{  
  findAndModify: <collection-name>,  
  query: <document>,  
  sort: <document>,  
  remove: <boolean>,  
  update: <document or aggregation pipeline>, // Changed in MongoDB 4.2  
  new: <boolean>,  
  fields: <document>,  
  upsert: <boolean>,  
  bypassDocumentValidation: <boolean>,  
  writeConcern: <document>,  
  collation: <document>,  
  arrayFilters: <array>  
}  

 参数字段：

fields: { <field1>: 1, <field2>: 1, ... }

collation: {
   locale: <string>,
   caseLevel: <boolean>,
   caseFirst: <string>,
   strength: <int>,
   numericOrdering: <boolean>,
   alternate: <string>,
   maxVariable: <string>,
   backwards: <boolean>
}

示例：

db.runCommand(  
  {  
    findAndModify: "book",  
    query: { name: "MongoDB" },  
    sort: { rating: 4 },  
    update: { $inc: { price: 1 } },  
    upsert: true  
  }  
)