Mongodb操作详解续

心已赠人 2022-06-01 07:07 173阅读 0赞

> 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" \}  
> 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  
1  
> 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" \}  
>  
  
> 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 \}  
> 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  
        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