persons该文件的数据如下面的:
> db.persons.find() { "_id" : 2, "name" : 2 } { "_id" : 3, "name" : 3 }
> db.persons.update({_id:4},{_id:4,name:4}) WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 }) > db.persons.find() { "_id" : 2, "name" : 2 } { "_id" : 3, "name" : 3 }
做完update操作，依旧看不到_id:4的记录。由于update方法须要一个true指示器。才会对查询不到的记录进行insert操作：
> db.persons.update({_id:4},{_id:4,name:4},true) WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : 4 }) > db.persons.find() { "_id" : 2, "name" : 2 } { "_id" : 3, "name" : 3 } { "_id" : 4, "name" : 4 }
现有需求。将persons文档中的name为"3"的改成"33"
> db.persons.update({name:"3"},{$set:{name:"33"}},false,true)
false含义:若查不到name:"33"的键值对，则不运行插入操作，true含义:表示是批量更新
为persons添加age:"88"属性
> db.persons.update({name:"4"},{$set:{age:"88"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4", "age" : "88" }
将age加2
> db.persons.update({name:"4"},{$inc:{age:2}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4", "age" : 90 }
将age属性拿走：
> db.persons.update({age:90},{$unset:{age:1}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" }
给persons文档添加一条记录，_id为5
> db.persons.insert({_id:5,name:5,books:[]}) WriteResult({ "nInserted" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "name" : 5, "books" : [ ] }
给books数组添加一个元素:"js"和"extjs4.0"
> db.persons.update({_id:5},{$push:{books:"js"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "name" : 5, "books" : [ "js" ] }
> db.persons.update({_id:5},{$push:{books:"extjs4.0"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "name" : 5, "books" : [ "js", "extjs4.0" ] }
创建一个新的classes数组:
> db.persons.update({_id:5},{$push:{classes:"01class"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "name" : 5, "books" : [ "js", "extjs4.0" ], "classes" : [ "01class" ] }
为calsses数组一次添加几个元素:
> db.persons.update({_id:5},{$pushAll:{classes:["02class","03class","04class"]}} ) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "name" : 5, "books" : [ "js", "extjs4.0" ], "classes" : [ "01class" , "02class", "03class", "04class" ] }
删除_id是5的记录,并创建一个新的_id是5的记录,使用$addToSet,此命令会检查要加入的元素在数组里面是不是存在，存在就不会再加入。否则会加入:
> db.persons.remove({_id:5}) WriteResult({ "nRemoved" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } > db.persons.insert({_id:5,books:["js"]}) WriteResult({ "nInserted" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "js" ] } > db.persons.update({_id:5},{$addToSet:{books:"js"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "js" ] } > db.persons.update({_id:5},{$addToSet:{books:"java"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "js", "java" ] } > db.persons.update({_id:5},{$addToSet:{books:"mongo"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "js", "java", "mongo" ] }
删除books数组的第一个元素:"js"。使用$pop命令:
> db.persons.update({_id:5},{$pop:{books:-1}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "java", "mongo" ] } > db.persons.update({_id:5},{$pop:{books:1}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "java" ] }
-1代表第一个元素，1代表最后一个元素
也能够使用pull命令一次删除一个指定的元素:
> db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "java", "mongo", "js" ] } > db.persons.update({_id:5},{$pull:{books:"js"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ "java", "mongo" ] }
$pullAll命令能够一次指定多个要删除的元素:
> db.persons.update({_id:5},{$pullAll:{books:["java","mongo"]}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ ] }
创建一条新的记录_id为6:
> db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ ] } { "_id" : 6, "books" : [ { "type" : "js", "name" : "extjs4.0" }, { "type" : "db" , "name" : "mongodb" }, { "type" : "js", "name" : "jquery" } ] }
为type是js的books元素加入pens:"too long"属性。使用.符号一定使用双引號引用
> db.persons.update({"books.type":"js"},{$set:{"books.$.author":"tom"}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4, "name" : "4" } { "_id" : 5, "books" : [ ] } { "_id" : 6, "books" : [ { "type" : "js", "name" : "extjs4.0", "author" : "tom" }, { "type" : "db", "name" : "mongodb" }] }
db.persons.update({"books.type":"js"},{$set:{"books.$.pens":"too long"}})
推断数组元素运行插入操作，反复的元素不会被插入第二次:
> db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4 } { "_id" : 5, "books" : [ "js" ] }
> db.persons.update({_id:5},{$addToSet:{books:{$each:["js","db","java"]}}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.persons.find() { "_id" : 2, "name" : "33" } { "_id" : 3, "name" : "33" } { "_id" : 4 } { "_id" : 5, "books" : [ "js", "db", "java" ] }
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