MongoDB Learning Notes (i)

Introduction: MongoDB comes with a JavaScript shell client, so it supports JavaScript syntax and most functions.

Introduction to MongoDB Common basic data types:

1. NULL: null or non-existent field
2. Boolean:true,false
3. Numeric type: The default value type in MongoDB is double, you can use the Numberint () function and the Numberlong () function to specify a field as Integer and Long Integer, respectively.
4. String:
5. Date: new Date (). GetTime ();//Gets the timestamp of the current time
6. Array: Var uarray=["Zhang San", "John Doe", "Harry"];

MongoDB Basic Operations

Add Data:　　　

Monomer Insert:

var p1 ={    "name": "Zhang Jie"    ,"age": Numberint ("" "),//  The default value type in MongoDB is double    "sex":false}db.user.insert (p1);

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BULK INSERT:

1. Insert an array directly:

 var  p2=[{ "name": "Zhang Jie"   Age: Numberint ("
   
    // 
        In MongoDB, the value type defaults to double  "sex": 
    false  
     " { "name": "Li Na" 
    " age ": Numberint (" "), // mongodb default is double  "sex": true
       "name": "RMB" ,  "age ": Numberint (" "), // mongodb defaults to double  "Sex": true  }]db.user.insert (p2);  
   

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2. Circular Insertion

varP2=[    {        "Name": "Li Chen",        "Age": Numberint ("28"),//the value type in MongoDB defaults to double"Sex":false    },    {        "Name": "Deng Chao",        "Age": Numberint ("33"),//the value type in MongoDB defaults to double"Sex":false    },    {        "Name": "Zheng Kai",        "Age": Numberint ("28"),//the value type in MongoDB defaults to double"Sex":false    }] for(vari=0;i<p2.length;i++) {Db.user.insert (p2[i]);}

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Delete data

Delete all documents in the user collection:

Db.user.remove (); // Delete all documents in the user collection

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To delete the specified collection:

var where={    "name": "Zheng Kai"};d B.user.remove (where); // Delete all documents with "name" as "Zheng Kai" in the user collection

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Delete a collection directly

Db.user.drop (); // Delete User Collection

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MongoDB Learning Notes (i)