node. JS manipulating the MongoDB database

Link database:

varMongo=require ("MongoDB"); varhost= "localhost"; varport=MONGO. Connection.default_port; varServer=NewMongo. Server (host,port,{auto_reconnect:true});//Server server where the database is created vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});//To Create a database objectDb.open (function(ERR,DB) {//connecting to a database     if(ERR)Throwerr; Else{Console.log ("Database connection successfully established");     Db.close (); } }); Db.on ("Close",function(ERR,DB) {//Close the database     if(ERR)Throwerr; ElseConsole.log ("Successfully closed database.")); });

Insert Data :

Output data document content in console after inserting data

 varMongo=require ("MongoDB"); varhost= "localhost"; varport=MONGO. Connection.default_port; varServer=NewMongo. Server (host,port,{auto_reconnect:true});//Server server where the database is created vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});//To Create a database objectDb.open (function(ERR,DB) {//connecting to a database     if(ERR)Throwerr; Else{db.collection ("Users",function(err,collection) {Collection.insert ({username:"Hope", FirstName: "Li"},function(Err,docs) {console.log (docs);             Db.close ();         });            }); } }); Db.on ("Close",function(ERR,DB) {//Close the database     if(ERR)Throwerr; ElseConsole.log ("Successfully closed database.")); });

Close Database db.close ([Forceclose],[callback]);

When Forceclose is true, the database is forced to close, and when the database is closed, open can no longer be used to open the database.

When Forceclose is false, the database is not forced to close, and when the database is closed, it can be opened again using open.

When Foreclose is true:

varMongo=require ("MongoDB"); varhost= "localhost"; varport=MONGO. Connection.default_port; varServer=NewMongo. Server (host,port,{auto_reconnect:true});//Server server where the database is created vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});//To Create a database objectDb.open (function(ERR,DB) {//connecting to a database     if(ERR)Throwerr; Else{db.collection ("Users",function(err,collection) {Collection.insert ({username:"Hope", FirstName: "Li"},function(Err,docs) {console.log (docs); Db.close (false);         });     }); } }); Db.once ("Close",function(ERR,DB) {//Close the database     if(ERR)Throwerr; Else{Db.open (function(err,db) {db.collection ("Users",function(err,collection) {Collection.insert ({username:"Three", FirstName: "Zhang"},function(err,docs) {if(ERR)Throwerr; Else{console.log (docs); Db.close (true);         }                 })             });     }); } });

reading Data

varMongo=require ("MongoDB");varhost= "localhost";varport=MONGO. Connection.default_port;varServer=mongo. Server (host,port,{auto_reconnect:true});vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});d B.open (function(err,db) {db.collection ("Users",function(err,collection) {if(ERR)Throwerr; Else{collection.find ({}). ToArray (function(err,docs) {if(ERR)Throwerr; Else{console.log (docs);                Db.close ();        }            }); }    });});

Search with query criteria

varMongo=require ("MongoDB");varhost= "localhost";varport=MONGO. Connection.default_port;varServer=mongo. Server (host,port,{auto_reconnect:true});vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});d B.open (function(err,db) {db.collection ("Users",function(err,collection) {if(ERR)Throwerr; Else{collection.find ({username:{$inch: ["Yan Si", "Three"]}}). ToArray (function(err,docs) {if(ERR)Throwerr; Else{console.log (docs);                Db.close ();        }            }); }    });});

insert a batch of data and search Type==food and the Price field value is less than 10

varMongo=require ("MongoDB");varhost= "localhost";varport=MONGO. Connection.default_port;varServer=mongo. Server (host,port,{auto_reconnect:true});vardb=NewMongo. Db ("Node-mongo-examples", Server,{safe:true});vardocs=[{type:"Food", price:11}, {type:"Food", price:10}, {type:"Food", price:9}, {type:"Food", price:8}, {type:"Book", Price:9}];d B.open (function(err,db) {db.collection ("Goods",function(err,collection) {if(ERR)Throwerr; Else{collection.insert (docs,function(err,docs) {if(ERR)Throwerr; Else{collection.find ({type:"Food", price:{$lt: 10}}). ToArray (function(err,docs) {if(ERR)Throwerr; Else{console.log (docs);                            Db.close ();                }                        }                    ); }            })        }    });});

The expression in a query :

Collection.find ({$or: [{type:' food '}, {price:{$lt:Ten}}]})

node. JS manipulating the MongoDB database