mongodb db.collection.remove用法
对于db.collection.remove需要加入加入一个query才能正常运行,否则仅仅运行remove()将会报错,例如:
> for(var i=0;i<100000;i++){ db.c3.insert({name:”user”,age:i}) }
>db.c3.remove();2018-05-03 T21:20:21.275+0800 E QUERY Error: remove needs a query at Error () at DBCollection._parseRemove (src/mongo/shell/collection.js:305:32) at DBCollection.remove (src/mongo/shell/collection.js:328:23) at (shell):1:16 at src/mongo/shell/collection.js:305如上语句 仅仅运行 db.dbdao_stuff.remove(); 会报错 Error: remove needs a query> db.c3.remove({});WriteResult({ "nRemoved" : 1000001 })
这时候加入 remove({}); 即可删除所有document
db.collection.remove有以下2种用法:
db.collection.remove( <query>, <justOne> ) 或者 db.collection.remove( <query>, { justOne: <boolean>, writeConcern: <document> } )
justone=>TRUE 时仅仅删除一条符合条件的document , writeConcern是关于safe write的