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发表于 2011-12-23 02:27 |只看该作者 |倒序浏览

<DIV>2011-01-07<BR>mongodb update，save操作说明博客分类：编程<BR>MongoDBSQL编程PHPBlog.原文地址：<a href="http://hi.baidu.com/farmerluo/blog/item/9a23cb13a819bb2fdd540188.html" target="_blank">http://hi.baidu.com/farmerluo/blog/item/9a23cb13a819bb2fdd540188.html</A></DIV>
<DIV> </DIV>
<DIV>MongoDB update数据语法<BR>2010年05月13日星期四 16:16<BR>在前面的文章“mongodb 查询的语法 ”里，我介绍了Mongodb的常用查询语法，Mongodb的update操作也有点复杂，我结合自己的使用经验，在这里介绍一下，给用mongodb的朋友看看，也方便以后自己用到的时候查阅：</DIV>
<DIV>注：在这篇文章及上篇文章内讲的语法介绍都是在mongodb shell环境内的，和真正运用语言编程（如java,php等）使用时，在使用方法上会有一些差别，但语法(如查询条件，$in,$inc等)是一样的。</DIV>
<DIV>本文是参考官方文档来介绍的，之所以有官方文档还要在这介绍，一方面是就当翻译，毕竟每次要用时去看英文文档比较累，第二是官方文档讲解比较简单，有时光看官方文档不好理解，我在实际操作的情况下可以做些补充。</DIV>
<DIV>好了，不多说了，下面正式开始：</DIV>
<DIV>mongodb更新有两个命令：</DIV>
<DIV>1).update()命令 </DIV>
<DIV>db.collection.update( criteria, objNew, upsert, multi )</DIV>
<DIV>criteria : update的查询条件，类似sql update查询内where后面的<BR>objNew   : update的对象和一些更新的操作符（如$,$inc...）等，也可以理解为sql update查询内set后面的<BR>upsert   : 这个参数的意思是，如果不存在update的记录，是否插入objNew,true为插入，默认是false，不插入。<BR>multi    : mongodb默认是false,只更新找到的第一条记录，如果这个参数为true,就把按条件查出来多条记录全部更新。</DIV>
<DIV>例：<BR>db.test0.update( { "count" : { $gt : 1 } } , { $set : { "test2" : "OK"} } ); 只更新了第一条记录<BR>db.test0.update( { "count" : { $gt : 3 } } , { $set : { "test2" : "OK"} },false,true ); 全更新了<BR>db.test0.update( { "count" : { $gt : 4 } } , { $set : { "test5" : "OK"} },true,false ); 只加进去了第一条<BR>db.test0.update( { "count" : { $gt : 5 } } , { $set : { "test5" : "OK"} },true,true ); 全加进去了<BR>db.test0.update( { "count" : { $gt : 15 } } , { $inc : { "count" : 1} },false,true );全更新了<BR>db.test0.update( { "count" : { $gt : 10 } } , { $inc : { "count" : 1} },false,false );只更新了第一条</DIV>
<DIV>2).save()命令 </DIV>
<DIV>db.collection.save( x )</DIV>
<DIV>x就是要更新的对象，只能是单条记录。</DIV>
<DIV>如果在collection内已经存在一个和x对象相同的"_id"的记录。mongodb就会把x对象替换collection内已经存在的记录，否则将会插入x对象，如果x内没有_id,系统会自动生成一个再插入。相当于上面update语句的upsert=true,multi=false的情况。</DIV>
<DIV>例：<BR>db.test0.save({count:40,test1:"OK"}); #_id系统会生成<BR>db.test0.save({_id:40,count:40,test1:"OK"}); #如果test0内有_id等于40的，会替换，否则插入。</DIV>
<DIV><BR>mongodb的更新操作符：</DIV>
<DIV>1) $inc </DIV>
<DIV>用法：{ $inc : { field : value } }</DIV>
<DIV>意思对一个数字字段field增加value，例：</DIV>
<DIV>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 16, "test1" : "TESTTEST", "test2" : "OK", "test3" : "TESTTEST", "test4" : "OK", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $inc : { "count" : 1 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 17, "test1" : "TESTTEST", "test2" : "OK", "test3" : "TESTTEST", "test4" : "OK", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $inc : { "count" : 2 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 19, "test1" : "TESTTEST", "test2" : "OK", "test3" : "TESTTEST", "test4" : "OK", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $inc : { "count" : -1 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : "TESTTEST", "test2" : "OK", "test3" : "TESTTEST", "test4" : "OK", "test5" : "OK" }</DIV>
<DIV><BR>2) $set </DIV>
<DIV>用法：{ $set : { field : value } }</DIV>
<DIV>就是相当于sql的set field = value，全部数据类型都支持$set。例：<BR>> db.test0.update( { "_id" : 15 } , { $set : { "test1" : "testv1","test2" : "testv2","test3" : "testv3","test4" : "testv4" } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : "testv1", "test2" : "testv2", "test3" : "testv3", "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>3) $unset </DIV>
<DIV>用法：{ $unset : { field : 1} }</DIV>
<DIV>顾名思义，就是删除字段了。例：<BR>> db.test0.update( { "_id" : 15 } , { $unset : { "test1":1 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test2" : "testv2", "test3" : "testv3", "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $unset : { "test2": 0 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test3" : "testv3", "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $unset : { "test3":asdfasf } } );<BR>Fri May 14 16:17:38 JS Error: ReferenceError: asdfasf is not defined (shell):0</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $unset : { "test3":"test" } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>没看出field : 1里面的1是干什么用的，反正只要有东西就行。</DIV>
<DIV><BR>4) $push </DIV>
<DIV><BR>用法：{ $push : { field : value } }</DIV>
<DIV>把value追加到field里面去，field一定要是数组类型才行，如果field不存在，会新增一个数组类型加进去。例：</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $set : { "test1" : ["aaa","bbb"] } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $push : { "test1": "ccc" } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb", "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $push : { "test2": "ccc" } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb", "ccc" ], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $push : { "test1": ["ddd","eee"] } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb", "ccc", [ "ddd", "eee" ] ], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }5) $pushAll </DIV>
<DIV>用法：{ $pushAll : { field : value_array } }</DIV>
<DIV>同$push,只是一次可以追加多个值到一个数组字段内。例：</DIV>
<DIV>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb", "ccc", [ "ddd", "eee" ] ], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $pushAll : { "test1": ["fff","ggg"] } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "aaa", "bbb", "ccc", [ "ddd", "eee" ], "fff", "ggg" ], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV>6)  $addToSet </DIV>
<DIV><BR>用法：{ $addToSet : { field : value } }</DIV>
<DIV>增加一个值到数组内，而且只有当这个值不在数组内才增加。例：<BR>> db.test0.update( { "_id" : 15 } , { $addToSet : { "test1": {$each : ["444","555"] } } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "aaa",<BR>        "bbb",<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444",<BR>        "555"<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }<BR>> db.test0.update( { "_id" : 15 } , { $addToSet : { "test1": {$each : ["444","555"] } } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "aaa",<BR>        "bbb",<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444",<BR>        "555"<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }<BR>> db.test0.update( { "_id" : 15 } , { $addToSet : { "test1": ["444","555"]  } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "aaa",<BR>        "bbb",<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444",<BR>        "555",<BR>        [<BR>                "444",<BR>                "555"<BR>        ]<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }<BR>> db.test0.update( { "_id" : 15 } , { $addToSet : { "test1": ["444","555"]  } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "aaa",<BR>        "bbb",<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444",<BR>        "555",<BR>        [<BR>                "444",<BR>                "555"<BR>        ]<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV><BR>7) $pop</DIV>
<DIV><BR>删除数组内的一个值</DIV>
<DIV>用法：<BR>删除最后一个值：{ $pop : { field : 1  } }删除第一个值：{ $pop : { field : -1  } }</DIV>
<DIV>注意，只能删除一个值，也就是说只能用1或-1，而不能用2或-2来删除两条。mongodb 1.1及以后的版本才可以用，例：<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "bbb",<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444"<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }<BR>> db.test0.update( { "_id" : 15 } , { $pop : { "test1": -1 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [<BR>        "ccc",<BR>        [<BR>                "ddd",<BR>                "eee"<BR>        ],<BR>        "fff",<BR>        "ggg",<BR>        [<BR>                "111",<BR>                "222"<BR>        ],<BR>        "444"<BR>], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }<BR>> db.test0.update( { "_id" : 15 } , { $pop : { "test1": 1 } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "ccc", [ "ddd", "eee" ], "fff", "ggg", [ "111", "222" ] ], "test2" : [ "ccc" ], "test4" : "testv4",<BR>"test5" : "OK" }</DIV>
<DIV>8) $pull</DIV>
<DIV><BR>用法：$pull : { field : value } }</DIV>
<DIV>从数组field内删除一个等于value值。例：<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "ccc", [ "ddd", "eee" ], "fff", "ggg", [ "111", "222" ] ], "test2" : [ "ccc" ], "test4" : "testv4",<BR>"test5" : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $pull : { "test1": "ggg" } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "ccc", [ "ddd", "eee" ], "fff", [ "111", "222" ] ], "test2" : [ "ccc" ], "test4" : "testv4", "test5"<BR> : "OK" }</DIV>
<DIV>9) $pullAll</DIV>
<DIV><BR>用法：{ $pullAll : { field : value_array } }</DIV>
<DIV>同$pull,可以一次删除数组内的多个值。例：<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ "ccc", [ "ddd", "eee" ], "fff", [ "111", "222" ] ], "test2" : [ "ccc" ], "test4" : "testv4", "test5"<BR> : "OK" }</DIV>
<DIV>> db.test0.update( { "_id" : 15 } , { $pullAll : { "test1": [ "ccc" , "fff" ] } } );<BR>> db.test0.find( { "_id" : 15 } );<BR>{ "_id" : { "floatApprox" : 15 }, "count" : 18, "test1" : [ [ "ddd", "eee" ], [ "111", "222" ] ], "test2" : [ "ccc" ], "test4" : "testv4", "test5" : "OK" }</DIV>
<DIV><BR>10) $ 操作符</DIV>
<DIV><BR>$是他自己的意思，代表按条件找出的数组里面某项他自己。呵呵，比较坳口。看一下官方的例子：</DIV>
<DIV>> t.find()<BR>{ "_id"<BR> : ObjectId("4b97e62bf1d8c7152c9ccb74"<BR>), "title"<BR> : "ABC"<BR>,  "comments"<BR> : [ { "by"<BR> : "joe"<BR>, "votes"<BR> : 3 }, { "by"<BR> : "jane"<BR>, "votes"<BR> : 7 } ] }</DIV>
<DIV>> t.update( {'comments.by':'joe'}, {$inc:{'comments.$.votes':1}}, false<BR>, true<BR> )</DIV>
<DIV>> t.find()<BR>{ "_id"<BR> : ObjectId("4b97e62bf1d8c7152c9ccb74"<BR>), "title"<BR> : "ABC"<BR>,  "comments"<BR> : [ { "by"<BR> : "joe"<BR>, "votes"<BR> : 4 }, { "by"<BR> : "jane"<BR>, "votes"<BR> : 7 } ] }</DIV>
<DIV>需要注意的是，$只会应用找到的第一条数组项，后面的就不管了。还是看例子：</DIV>
<DIV>> t.find();<BR>{ "_id"<BR> : ObjectId("4b9e4a1fc583fa1c76198319"<BR>), "x"<BR> : [ 1, 2, 3, 2 ] }<BR>> t.update({x: 2}, {$inc: {"x.$"<BR>: 1}}, false<BR>, true<BR>);<BR>> t.find();</DIV>
<DIV>还有注意的是$配合$unset使用的时候，会留下一个null的数组项，不过可以用{$pull:{x:null}}删除全部是null的数组项。例：<BR>> t.insert({x: [1,2,3,4,3,2,3,4]})<BR>> t.find()<BR>{ "_id"<BR> : ObjectId("4bde2ad3755d00000000710e"<BR>), "x"<BR> : [ 1, 2, 3, 4, 3, 2, 3, 4 ] }<BR>> t.update({x:3}, {$unset:{"x.$"<BR>:1}})<BR>> t.find()<BR>{ "_id"<BR> : ObjectId("4bde2ad3755d00000000710e"<BR>), "x"<BR> : [ 1, 2, null<BR>, 4, 3, 2, 3, 4 ] }</DIV>
<DIV>{ "_id"<BR> : ObjectId("4b9e4a1fc583fa1c76198319"<BR>), "x"<BR> : [ 1, 3, 3, 2 ] }</DIV>

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Chinaunix › 论坛 › 数据库技术 › NoSQL技术 › mongodb update，save操作说明

[MongoDB] mongodb update，save操作说明 [复制链接]