Mongodb操作详解（二）

> db.blog.find(null,{title:1}) //只查询title字段

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "title" : "My Blog Post" }

> db.blog.find(null,{title:1,_id:0}) //只查询title字段,并过滤掉_id字段

{ "title" : "My Blog Post" } www.zzzyk.com

> db.blog.find().sort({title:1}) //sort 以title字段升序查询--- 1表示升序，-1表示降序

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "title" : "My Blog Post", "conte

nt" : "Here's my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "

comments" : [ ] }

> db.blog.find().sort({title:1}).limit(2).skip(1) //隔一个，查询两个

> db.blog.find().count() //count集合函数

> db.blog.update({title:'My Blog Post'},{$set:{content:'Here is my blog post.'}}

//使用$set只更新content的内容，不然整个数据变为content字段值

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "title"

: "My Blog Post" }

> db.blog.update({title:'My Blog Post'},{$inc:{number:1}}) //number字段不存在，自动创建了

> db.blog.find() //看结果，就知道

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 1, "title" : "My Blog Post" }

> db.blog.update({title:'My Blog Post'},{$inc:{number:1}}) //number存在，number+1最终结果为2

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "title" : "My Blog Post" } www.zzzyk.com

> db.blog.update({title:'My Blog Post'},{$push:{push:1}}) //$push为数组类型字段添加一个值

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "push" : [ 1 ], "title" : "My Blog Post" }

> db.blog.update({title:'My Blog Post'},{$pop:{push:1}}) //$pop删除数组中的一个值

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "push" : [ ], "title" : "My Blog Post" }

> db.blog.ensureIndex({title:1}) //创建索引

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "push" : [ ], "title" : "My Blog Post" }

> db.blog.dropIndex({title:1}) //删除索引

{ "nIndexesWas" : 2, "ok" : 1 } www.zzzyk.com

> db.blog.ensureIndex({title:1},{unique:true}) //创建unique索引独立索引

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "push" : [ ], "title" : "My Blog Post" }

> db.blog.ensureIndex({title:1,number:-1}) //创建联合索引

> db.blog.find()

{ "_id" : ObjectId("50264a762d31a25926fc6e86"), "comments" : [ ], "content" : "H

ere is my blog post.", "created" : ISODate("2012-08-11T11:38:08.698Z"), "number"

: 2, "push" : [ ], "title" : "My Blog Post" }

> db.blog.dropIndex({title:1,number:-1})

{ "nIndexesWas" : 2, "ok" : 1 }

F:\Mongodb206\bin>mongodump.exe --db local --out backup //备份数据库local为backup文件夹中

connected to: 127.0.0.1

DATABASE: local to backup/local

local.blog to backup/local/blog.bson

1 objects www.zzzyk.com

local.system.indexes to backup/local/system.indexes.bson

1 objects

F:\Mongodb206\bin>mongorestore.exe -collection blog backup/local/blog //将备份数据还原

connected to: 127.0.0.1

DATABASE: local to backup/local

local.blog to backup/local/blog.bson

1 objects

local.system.indexes to backup/local/system.indexes.bson

1 objects