mongodb查询语句及mongoose操作数据库总结

1.查询某几个字段

    db.pers.find({age:15},{age:true,title:true});//查询age=15的记录的age和title字段;

mongoose操作数据库

var mongoose=require("mongoose");
var conn = mongoose.connect("mongodb://localhost/mytest");

var Schema = mongoose.Schema;
var ObjectId =  Schema.ObjectId;

var Person = new Schema({
    title:{type:String},
    age:{type:Number,min:5,max:20},
    meta:{
        likes:[String],
        birth:{type:String}
    }
});

var p = mongoose.model('per',Person);

var Blog = mongoose.model("per");


var blog1 = new Blog();
    blog1.title="Tom";
    blog1.age=17;
    blog1.meta={
        likes:"DOTA3",
        birth:"1989-06-19"
    };
//插入新纪录
    blog1.save(function(err){
        if(err){
            console.log(err);
            console.log("save failed");
        }else{
            console.log("success!");
        }
    });
//查找age=15的记录
    Blog.find({age:15},function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//查询age=15的记录的age和title字段;
    Blog.find({age:15},{age:true,title:true},function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//查询所有记录的age和title字段;
    Blog.find({},{age:true,title:true},function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//修改age=15的记录的title为"fuck2"
    var conditions = {age:15},
         update = {$set:{title:'fuck2'}};
    Blog.update(conditions,update,{},function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//链式写法

//查询title="JACK"的记录

   Blog.find().where('title').equals('JACK').exec(function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//查询age>10,从0开的3条记录的age,title字段
    Blog.find().where('age').gte(10).select('age title').skip(0).limit(3).exec(function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });
//查询age=15,从0开的3条记录的age,title字段
    Blog.find({age:15}).select('age title').skip(0).limit(3).exec(function(err,docs){
        if(!err){
            console.log(docs);
        }else{
            console.log(err);
        }
    });