做个总结，涉及到mongodb的常用命令、java driver查询、spring data mongodb的使用，group，map-reduce，aggregation framework等
关闭服务
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use admin
db.shutdownServer()
加锁
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use admin
db.runCommand({"fsync":1,"lock":1})
wang chaoqun
解锁
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use admin
db.$cmd.sys.unlock.findOne()
db.currentOp()
{"inprog":[]}
导出和导入
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mongodump -h 192.168.0.100:27017 -d mydb -o B:\mongo\dump
mongorestore -h 127.0.0.1:27017 --directoryperdb B:\mongo\dump
用户
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use admin
db.addUser('name','pwd')
db.system.users.find()
db.auth('name','pwd')
db.removeUser('name')
数据库
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db.copyDatabase('projectDB1', 'projectDB2')
db.projectDB1.drop()
db.dropDatabase()
增删改
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db.mycollection.inser,save,update...
索引
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db.user.ensureIndex({firstname: 1, lastname: 1}, {unique: true});
db.user.dropIndex('address.post_1')
查询
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db.mycollection.find,findOne,distinct.sort({'createTime',-1}).skip(3).limit(10)
db.user.insert({"name":"cq","age":28,"address":{"province":100,"city":101}})
db.user.find({"_id":ObjectId("52f830f3aab82981150db455")})
db.user.find({"address":{"province":100,"city":101}}) # one record
db.user.find({"address":{"city":101,"province":100}}) # nothing
db.user.find({"address.city":101,"address.province":100}) # one record
注意：key的顺序,因为MongoDB使用BSON的二进制数据格式技术
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db.user.find({creationTime:{$gt:1300000000000, $lte:1310000000000});
$elemMatch:前2个不对，匹配数组查询要用第3个
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db.blog.find({"comments.name": "foo", "comments.content": "bar"});
db.blog.find({"comments": {"name": "foo", "content": "bar"}});
db.blog.find({"comments":{"$elemMatch":{"name":"joke", "content":"bad good ugly"}}});
使用where可做运算
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db.reply.find({$where: "this.upCount+this.downCount<1"});
db.reply.find("this.upCount+this.downCount<1");
返回和排除字段
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db.user.find({"name":"cq"}, {age:1, address:0});
count
db.topic.find().skip(10).limit(5).count(); # 所有的记录数量
要返回限制的记录数量，要使用count(true)或count(非0)
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db.topic.find().skip(10).limit(5).count(true);
dbref关联
多查一
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> db . reply . findOne ({ creator : "wy" }, { creator : 1 , topic : 1 })
{
"_id" : ObjectId ( "52d3ae720b6316a72bb31c45" ),
"creator" : "wy" ,
"topic" : DBRef ( "topic" , ObjectId ( "52cf620a0b6307f6a0d44450" ))
}
> db . reply . findOne ({ creator : "wy" }). topic
DBRef ( "topic" , ObjectId ( "52cf620a0b6307f6a0d44450" ))
> db . reply . findOne ({ creator : "wy" }). topic . fetch ()
{
"_id" : ObjectId ( "52cf620a0b6307f6a0d44450" ),
"content" : "xxx" ,
"createtime" : NumberLong ( "1389322762932" ),
"creator" : "zzz"
...
}
一查多
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> topic = db . reply . findOne ({ creator : "wy" }). topic
DBRef ( "topic" , ObjectId ( "52cf620a0b6307f6a0d44450" ))
> db . reply . find ({ "topic" : topic }). count ()
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> topic = db . reply . findOne ({ creator : "wy" }). topic
DBRef ( "topic" , ObjectId ( "52cf620a0b6307f6a0d44450" ))
> db . reply . find ({ "topic.$id" : topic . $id }). count ()
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> topic = db . reply . findOne ({ creator : "wy" }). topic . fetch ()
{
"_id" : ObjectId ( "52cf620a0b6307f6a0d44450" ),
"content" : "xxx" ,
"createtime" : NumberLong ( "1389322762932" ),
"creator" : "zzz"
...
}
> db . reply . find ({ "topic.$id" : topic . _id }). count ()
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spring data mongodb
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Criteria cri = Criteria . where ( "topic.$id" ). is ( new ObjectId ( "52d8f8950b6316a72bb31c7c" ));
Reply reply = mongoTemplate . findOne ( Query . query ( cri ), Reply . class );
cri . andOperator ( Criteria . where ( "passedtime" ). gt ( fromTime ), Criteria . where ( "passedtime" ). lt ( toTime ));
// 错误的：Criteria.where("passedtime").gt(fromTime).and("passedtime").lt(toTime)
java driver 可以这样：
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String total = "this.upCount+this.downCount < " + minCount ;
BasicDBObject query = new BasicDBObject ( "$where" , total );
query . append ( "passedtime" , new BasicDBObject ( "$gt" , fromTime ). append ( "$lt" , toTime ));
// TODO query.append(other conditions);
// 返回字段
BasicDBObject keys = new BasicDBObject ();
keys . put ( "_id" , 1 );
keys . put ( "creator" , 1 );
MongoClient mongoClient = new MongoClient ( new ServerAddress ( "localhost" , 27017 ));
DB db = mongo . getDB ( "mydb" );
DBCollection collection = db . getCollection ( "test" );
long count = collection . count ( query );
DBCursor cursor = collection . find ( query , keys ). limit ( size );
for ( int i = 0 ; i < size ; i ++) {
DBObject e = cursor . next ();
String topicId = e . get ( "_id" ). toString ();
// TODO
}