【mongoDB 操作】--update, remove, $set, $push

对mongo进行简单的总结,当然可以阅读mongoDB的reference咯
https://docs.mongodb.com/v2.6/reference/method/db.collection.update/

元素的 增，删，改

1：增加和修改元素, 用update 和$set。更改数据库某个元素的某个字段 用 update和$set，（当然，如果这个字段不存在时，则创建它。）

语法如下：

db.collection.update(   <query>,   <update>,   {     upsert: <boolean>,     multi: <boolean>,     writeConcern: <document>   })

db.pr_goal_mapping.update({system_release: "TL16"},{$set: {goal_name:"NCDR"}},false,true) //更改符合条件的所有item。

参数说明：

EXAMPLE：
For example, given a books collection with the following document:

{  _id: 1,  item: "TBD",  stock: 0,  info: { publisher: "1111", pages: 430 },  tags: [ "technology", "computer" ],  ratings: [ { by: "ijk", rating: 4 }, { by: "lmn", rating: 5 } ],  reorder: false}

• the $inc operator to increment the stock field; and
• the $set operator to replace the value of the item field, the publisher field in the info embedded document, the tags field, and the second element in the ratings array.

db.books.update(   { _id: 1 },   {     $inc: { stock: 5 },     $set: {       item: "ABC123",       "info.publisher": "2222",       tags: [ "software" ],       "ratings.1": { by: "xyz", rating: 3 }     }   })

The updated document is the following:

{  "_id" : 1,  "item" : "ABC123",  "stock" : 5,  "info" : { "publisher" : "2222", "pages" : 430 },  "tags" : [ "software" ],  "ratings" : [ { "by" : "ijk", "rating" : 4 }, { "by" : "xyz", "rating" : 3 } ],  "reorder" : false}

例子2：
比如原始数据为：

> db.pci_hierarchy.find({branch:"tl16a_mp", test_hierarchy:/fsih hw cpri dm/}).pretty(){        "_id" : ObjectId("57bac95bcdadc2c83b2d1feb"),        "bl" : "lte-n",        "product" : "tdd-macro",        "branch" : "tl16a_mp",        "type" : "product",        "test_hierarchy" : "qt;qt1;fsih hw cpri dm",        "order" : 999,        "createtime" : 1471859035,        "updatetime" : 1471859035,        "active" : 1}

需要修改 “active” : 1 —> “active” : 0 则用：

> db.pci_hierarchy.update({branch:"tl16a_mp", test_hierarchy:/fsih hw cpri dm/}, {"$set": {"active": 0}})

更改后会有如下提示：

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

最后再次检查修改是否生效：

> db.pci_hierarchy.find({branch:"tl16a_mp", test_hierarchy:/fsih hw cpri dm/}).pretty(){        "_id" : ObjectId("57bac95bcdadc2c83b2d1feb"),        "bl" : "lte-n",        "product" : "tdd-macro",        "branch" : "tl16a_mp",        "type" : "product",        "test_hierarchy" : "qt;qt1;fsih hw cpri dm",        "order" : 999,        "createtime" : 1471859035,        "updatetime" : 1471859035,        "active" : 0}

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• 2： 删除元素， remove
• remove函数可以接受一个查询文档作为可选参数，给定这个参数后，只有符合条件的文档才被删除。

> db.pci_hierarchy.findOne({"name":"zhou"}){        "_id" : ObjectId("57d0bf74ff127ecc2ac2788d"),        "name" : "zhou",        "comments" : [                {                        "name" : "joe",                        "email" : "[e-mail]"                },                {                        "name" : "chang",                        "email" : "[e-mail]"                }        ],        "tel" : [                123,                321        ]}删除该元素：> db.pci_hierarchy.remove({"name":"zhou"})WriteResult({ "nRemoved" : 1 })> db.pci_hierarchy.findOne({"name":"zhou"})null>

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数组修改器

1. 增加或者修改：
   –如果数组已经存在，“$push”会向已有的数组末尾添加一个元素，要是不存在就创建一个新的数组。

原始数组：> db.pci_hierarchy.findOne({"name":"zhou"}){ "_id" : ObjectId("57d0bf74ff127ecc2ac2788d"), "name" : "zhou" }利用$push增加一个数组元素：> db.pci_hierarchy.update({"name":"zhou"}, {"$push": {"comments": {"name": "joe", "email": "[e-mail]"}}})WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })> db.pci_hierarchy.findOne({"name":"zhou"}){        "_id" : ObjectId("57d0bf74ff127ecc2ac2788d"),        "name" : "zhou",        "comments" : [                {                        "name" : "joe",                        "email" : "[e-mail]"                }        ]}再次增加comments的元素，修改成功。> db.pci_hierarchy.update({"name":"zhou"}, {"$push": {"comments": {"name": "chang", "email": "[e-mail]"}}})WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })> db.pci_hierarchy.findOne({"name":"zhou"}){        "_id" : ObjectId("57d0bf74ff127ecc2ac2788d"),        "name" : "zhou",        "comments" : [                {                        "name" : "joe",                        "email" : "[e-mail]"                },                {                        "name" : "chang",                        "email" : "[e-mail]"                }        ]}