MongoDB学习笔记【2】-- 试用
大部分内容根据MongoDB官方手册整理：http://docs.mongodb.org/manual/contents/
查看数据库
[root@slayer ~]# mongo MongoDB shell version: 2.2.3 connecting to: test > show dbs local (empty) test 0.0625GB >
使用use切换数据库，use一个新名字可以使用新数据库，MongoDB会等到插入数据才会建立
> use mydb switched to db mydb > show dbs local (empty) test 0.0625GB > db.mydb.insert({name:"slayer"}) > show dbs local (empty) mydb 0.0625GB test 0.0625GB >
find看内容
> db.mydb.find() { "_id" : ObjectId("50c950ab96c0253cce4a8c87"), "name" : "slayer" } >
换个方式插入。。
> a = {1 : "x"}
{ "1" : "x" }
> b = {2 : "y"}
{ "2" : "y" }
> db.mydb.insert(a, b)
> db.mydb.find()
{ "_id" : ObjectId("50c950ab96c0253cce4a8c87"), "name" : "slayer" }
{ "_id" : ObjectId("50c951ba96c0253cce4a8c88"), "1" : "x" }
> db.mydb.insert(b)
> db.mydb.find()
{ "_id" : ObjectId("50c950ab96c0253cce4a8c87"), "name" : "slayer" }
{ "_id" : ObjectId("50c951ba96c0253cce4a8c88"), "1" : "x" }
{ "_id" : ObjectId("50c951d096c0253cce4a8c89"), "2" : "y" }
可以看到insert不支持多个参数
用循环插入
> for (i=0; i<7; ++i) db.mydb.insert({value: i}) > db.mydb.find() { "_id" : ObjectId("50c950ab96c0253cce4a8c87"), "name" : "slayer" } { "_id" : ObjectId("50c951ba96c0253cce4a8c88"), "1" : "x" } { "_id" : ObjectId("50c951d096c0253cce4a8c89"), "2" : "y" } { "_id" : ObjectId("50c9661596c0253cce4a8c8a"), "value" : 0 } { "_id" : ObjectId("50c9661596c0253cce4a8c8b"), "value" : 1 } { "_id" : ObjectId("50c9661596c0253cce4a8c8c"), "value" : 2 } { "_id" : ObjectId("50c9661596c0253cce4a8c8d"), "value" : 3 } { "_id" : ObjectId("50c9661596c0253cce4a8c8e"), "value" : 4 } { "_id" : ObjectId("50c9661596c0253cce4a8c8f"), "value" : 5 } { "_id" : ObjectId("50c9661596c0253cce4a8c90"), "value" : 6 } >
继续插入
> db.mydb.xx.insert({1:3})
> db.mydb.xx.find()
{ "_id" : ObjectId("50c966b596c0253cce4a8c91"), "1" : 3 }
查看当前数据库 db 删除数据库 db.dropDatabase()
> db mydb > show dbs local (empty) mydb 0.0625GB test 0.0625GB > db.dropDatabase() { "dropped" : "mydb", "ok" : 1 } > show dbs local (empty) test 0.0625GB > db
使用游标和循环来打印内容
> var c = db.mydb.find() > while (c.hasNext()) printjson(c.next()) { "_id" : ObjectId("50c96b7196c0253cce4a8c92"), "value" : 0 } { "_id" : ObjectId("50c96b7196c0253cce4a8c93"), "value" : 1 } { "_id" : ObjectId("50c96b7196c0253cce4a8c94"), "value" : 2 } { "_id" : ObjectId("50c96b7196c0253cce4a8c95"), "value" : 3 } { "_id" : ObjectId("50c96b7196c0253cce4a8c96"), "value" : 4 } { "_id" : ObjectId("50c96b7196c0253cce4a8c97"), "value" : 5 } { "_id" : ObjectId("50c96b7196c0253cce4a8c98"), "value" : 6 } >
三个方法的官方说明：The hasNext() function returns true if the cursor has documents. The next() method returns the next document. The printjson() method renders the document in a JSON-like format.
hasNext() 返回游标是否指向文件，next 返回下一个文件。printjson 把文件用用类json格式打印出来。
使用游标的下标
> var c = db.mydb.find() > printjson(c[0]) { "_id" : ObjectId("50c96b7196c0253cce4a8c92"), "value" : 0 } > printjson(c[4]) { "_id" : ObjectId("50c96b7196c0253cce4a8c96"), "value" : 4 }
打印复杂点的json数据
> db.mydb.xx.insert({a : 1, b: {A : "x", B : {alpha : 0}}})
> var c = db.mydb.xx.find()
> printjson(c.next())
{
"_id" : ObjectId("50c96eee96c0253cce4a8c99"),
"a" : 1,
"b" : {
"A" : "x",
"B" : {
"alpha" : 0
}
}
}
>
查找元素
> db.mydb.find({value:0}) { "_id" : ObjectId("50c96b7196c0253cce4a8c92"), "value" : 0 } > db.mydb.insert({value:0, xx:"a"}) > db.mydb.find({value:0}) { "_id" : ObjectId("50c96b7196c0253cce4a8c92"), "value" : 0 } { "_id" : ObjectId("50c9707396c0253cce4a8c9a"), "value" : 0, "xx" : "a" } > db.mydb.find({value:0}).limit(1) { "_id" : ObjectId("50c96b7196c0253cce4a8c92"), "value" : 0 } >
最后看看各种help..
> help db.help() help on db methods db.mycoll.help() help on collection methods sh.help() sharding helpers rs.help() replica set helpers help admin administrative help help connect connecting to a db help help keys key shortcuts help misc misc things to know help mr mapreduce show dbs show database names show collections show collections in current database show users show users in current database show profile show most recent system.profile entries with time >= 1ms show logs show the accessible logger names show log [name] prints out the last segment of log in memory, 'global' is default use <db_name> set current database db.foo.find() list objects in collection foo db.foo.find( { a : 1 } ) list objects in foo where a == 1 it result of the last line evaluated; use to further iterate DBQuery.shellBatchSize = x set default number of items to display on shell exit quit the mongo shell >
MongoDB学习笔记【3】-- MongoDB C驱动使用
MongoDB学习笔记【4】-- MongoDB Java驱动使用
