-----1.新建索引

db.tblorders.dropIndexes();

db.tblorders.createIndex( { "OrderNo" : 1 },{background:true, name:"index_OrderNo"} );

db.hisorders.createIndex( { "orderno" : 1 },{background:true, name:"hisorders_index_orderno"} );





--ensureIndex已經降級
db.tblorders.ensureIndex({"OrderNo" : 1},{background:true, name:"index_OrderNo"});


db.orderlog.ensureIndex({"OrderNo":1},{background:true, name:"index_orderlog"});



-----2.查詢已有索引
語法：
> db.tblorders.getIndexes()

db.hisorders.getIndexes()


db.tblorders.find({OrderNo:"A2022823590918802334"}).forEach(printjson);

db.tblorders.find({OrderNo:"20130901010019880500"}).forEach(printjson);

db.tblorders.find({OrderNo:"A2013090106022059954"}).forEach(printjson);

db.tblorders.find({OrderNo:"H2013090103019884364"}).explain("executionStats");


db.tblorders.find({OrderNo:"H2013090103019884364"}).explain("executionStats");





-----3. 查詢索引大小
語法：
>  db.tblorders.totalIndexSize()e


----4.物件改名
use admin;

db.runCommand(
{
renameCollection:"jinrilog.orderlog201508",
to: "jinrilog.orderlog",
dropTarget: false
}
);



-----5.刪除索引

db.tblorders.dropIndexes();


-----6.刪除物件



--方法1：
> db.tblorders.drop() ;
true
> db.tblorders.find().count();
0
> show tables;
hisorders
t1
> 


---方法2:
db.tblorders.remove( { } );


db.collection.drop()    #是用來從資料庫中刪除一個數據集合包括索引

db.collection.remove()	#可以從一個集合中刪除所有文件，刪除匹配一個條件的所有文件，或者限制操作只刪除一條文件,逐條刪除.




---7.kill session

> db.currentOp()
{
	"inprog" : [
		{
			"desc" : "conn189",
			"threadId" : "0x3e083380",
			"connectionId" : 189,
			"opid" : 953531,  --程序ID
			"active" : true,
			"secs_running" : 852,
			"microsecs_running" : NumberLong(852352681),
			"op" : "remove",
			"ns" : "jinri.tblorders",
			"query" : {
				
			},
			"client" : "192.168.0.180:46773",
			"numYields" : 148618,
			"locks" : {
				"Global" : "w",
				"Database" : "w",
				"Collection" : "w"
			},
			"waitingForLock" : false,
			"lockStats" : {
				"Global" : {
					"acquireCount" : {
						"r" : NumberLong(148619),
						"w" : NumberLong(148619)
					}
				},
				"Database" : {
					"acquireCount" : {
						"w" : NumberLong(148619)
					},
					"acquireWaitCount" : {
						"w" : NumberLong(3)
					},
					"timeAcquiringMicros" : {
						"w" : NumberLong(388)
					}
				},
				"Collection" : {
					"acquireCount" : {
						"w" : NumberLong(148619)
					}
				}
			}
		}
	]
}


> db.killOP(953531)
{ "info" : "attempting to kill op" }