MongoDB数据更新
MongoDB数据更新可以使用update()函数。
db.collection.update( criteria, objNew,upsert, multi )
update()函数接受以下四个参数：
• criteria : update的查询条件，类似sql update查询内where后面的。
• 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
• 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。
• 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。
>db.blog.insert({"name":"jack","id":88}) --插入记录
WriteResult({ "nInserted" : 1 })
>db.blog.insert({"name":"jack","id":88}) --插入记录
WriteResult({ "nInserted" : 1 })
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"jackwangwei" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack", "id" : 88 }
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack", "id" : 88 }
>
>
> db.blog.update({ "name" :"jack"},{"name":"jack12"}, { "upsert" :true });
WriteResult({ "nMatched" : 1,"nUpserted" : 0, "nModified" : 1 })
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"jackwangwei" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12" } --只更新一条记录，并且id没有了，相当于删除了字段
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack", "id" : 88 }
>
> db.blog.update({ "name" :"jack"},{$set:{"name":"jack34"}}) 加上$set更新
WriteResult({ "nMatched" : 1,"nUpserted" : 0, "nModified" : 1 })
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"jackwangwei" }
{ "_id" : ObjectId("543b3115a55dc3b8e7c4e932"),"author33" : "jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12" }
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack34", "id" : 88 }
>
> db.blog.update({"name" : "jack12"},{$set:{"id":"jack34"}})
WriteResult({ "nMatched" : 1,"nUpserted" : 0, "nModified" : 1 })
>
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"jackwangwei" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12", "id" : "jack3
4" } --相当于添加了字段并赋值
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack34", "id" : 88 }
>
> db.blog.update({ "name" :"wangwei"},{$set:{"id":"jack34"}},{ "upsert" : true
}) --更新的记录不存在就插入
WriteResult({
"nMatched" : 0,
"nUpserted" : 1,
"nModified" : 0,
"_id" : ObjectId("543b386ca55dc3b8e7c4e933")
})
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "cont
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" : ObjectId("5438df80a7ccb1d4ecc7571e"),"author" : "jackwangwei" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12", "id" : "jack
4" }
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack34", "id" : 88 }
{ "_id" :ObjectId("543b386ca55dc3b8e7c4e933"), "name" :"wangwei", "id" : "jac
34" }
>
> db.blog.update({ "id" :"jack34"},{$set:{"id":"jack"}},{multi:true}) –默认更新，把multi设置为true可以更新多行
WriteResult({ "nMatched" : 2, "nUpserted": 0, "nModified" : 2 })
>
>
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"jackwangwei" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12", "id" : "jack"
}
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" : "jack34","id" : 88 }
{ "_id" :ObjectId("543b386ca55dc3b8e7c4e933"), "name" :"wangwei", "id" : "jack
" }
>
MongoDB Save() 方法也可以实现更新
save() 方法替换现有的文档和通过新的文档 save() 方法
语法
MongoDB 的 save() 方法的基本语法如下：
>db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})
> db.blog.save({"_id" :ObjectId("5438df80a7ccb1d4ecc7571e"),"author":"save"})
WriteResult({ "nMatched" : 1,"nUpserted" : 0, "nModified" : 1 })
> db.blog.find()
{ "_id" :ObjectId("5438dd3fa7ccb1d4ecc7571d"), "title" : "myblog post", "conte
nt" : "here is blog past","date" : ISODate("2014-10-11T07:32:55.652Z")}
{ "_id" :ObjectId("5438df80a7ccb1d4ecc7571e"), "author" :"save" }
{ "_id" :ObjectId("543b3115a55dc3b8e7c4e932"), "author33" :"jackwangwei" }
{ "_id" :ObjectId("543b35e56f525084e39aab40"), "name" :"jack12", "id" : "jack"
}
{ "_id" :ObjectId("543b35e76f525084e39aab41"), "name" :"jack34", "id" : 88 }
{ "_id" :ObjectId("543b386ca55dc3b8e7c4e933"), "name" :"wangwei", "id" : "jack
" }
>
只更新第一条记录：
db.test0.update( { "count" : { $gt: 1 } } , { $set : { "test2" : "OK"} } );
全部更新：
db.test0.update( { "count" : { $gt: 3 } } , { $set : { "test2" : "OK"} },false,true );
只添加第一条：
db.test0.update( { "count" : { $gt: 4 } } , { $set : { "test5" : "OK"} },true,false );
全部添加加进去:
db.test0.update( { "count" : { $gt: 5 } } , { $set : { "test5" : "OK"} },true,true );
全部更新：
db.test0.update( { "count" : { $gt: 15 } } , { $inc : { "count" : 1} },false,true );
只更新第一条记录：
db.test0.update( { "count" : { $gt: 10 } } , { $inc : { "count" : 1} },false,false );