mongodb學習(查詢詳解)

mongodb學習(查詢詳解)

在前面幾篇博客當中學習到了修改的詳細操作，可是對於查詢卻一直是查詢所有的記錄，這篇文章將會帶大家詳細學習查詢的操作。

查詢指定字段
在進行正式的學習之前，我先將需要的數據插入數據庫中，如下：

var students= [{
    name:"jim",
    age:25,
    email:"[email protected]",
    c:89,m:96,e:87,
    country:"USA",
    books:["JS","C++","EXTJS","MONGODB"]
},
{
    name:"tom",
    age:25,
    email:"[email protected]",
    c:75,m:66,e:97,
    country:"USA",
    books:["PHP","JAVA","EXTJS","C++"]
},
{
    name:"lili",
    age:26,
    email:"[email protected]",
    c:75,m:63,e:97,
    country:"USA",
    books:["JS","JAVA","C#","MONGODB"]
},
{
    name:"zhangsan",
    age:27,
    email:"[email protected]",
    c:89,m:86,e:67,
    country:"China",
    books:["JS","JAVA","EXTJS","MONGODB"]
},
{
    name:"lisi",
    age:26,
    email:"[email protected]",
    c:53,m:96,e:83,
    country:"China",
    books:["JS","C#","PHP","MONGODB"]
},
{
    name:"wangwu",
    age:27,
    email:"[email protected]",
    c:45,m:65,e:99,
    country:"China",
    books:["JS","JAVA","C++","MONGODB"]
},
{
    name:"zhaoliu",
    age:27,
    email:"[email protected]",
    c:99,m:96,e:97,
    country:"China",
    books:["JS","JAVA","EXTJS","PHP"]
},
{
    name:"piaoyingjun",
    age:26,
    email:"[email protected]",
    c:39,m:54,e:53,
    country:"Korea",
    books:["JS","C#","EXTJS","MONGODB"]
},
{
    name:"lizhenxian",
    age:27,
    email:"[email protected]",
    c:35,m:56,e:47,
    country:"Korea",
    books:["JS","JAVA","EXTJS","MONGODB"]
},
{
    name:"lixiaoli",
    age:21,
    email:"[email protected]",
    c:36,m:86,e:32,
    country:"Korea",
    books:["JS","JAVA","PHP","MONGODB"]
},
{
    name:"zhangsuying",
    age:22,
    email:"[email protected]",
    c:45,m:63,e:77,
    country:"Korea",
    books:["JS","JAVA","C#","MONGODB"]
}]

for(var i = 0;i<students.length;i++){
    db.students.insert(students[i])
}