Node. js example of mongoDB operations _ node. js

Here we will share with you node. examples of js operations on the mongoDB database, including connecting to the database, inserting data, closing the database, reading data, and inserting data, are very comprehensive. We recommend this to our partners. Connect to database

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = new mongo. Server (host, port, {auto_reconnect: true}); // the server on which the database is created
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true}); // create a database object
Db. open (function (err, db) {// connect to the database
If (err)
Throw err;
Else {
Console. log ("database connection established successfully ");
Db. close ();
}
});
Db. on ("close", function (err, db) {// close the database
If (err) throw err;
Else console. log ("database closed successfully .");
});

Insert data:

After inserting data, output the content of the data document in the console

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = new mongo. Server (host, port, {auto_reconnect: true}); // the server on which the database is created
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true}); // create a database object
Db. open (function (err, db) {// connect to the database
If (err)
Throw err;
Else {
Db. collection ("users", function (err, collection ){
Collection. insert ({username: "panpan", firstname: "Li"}, function (err, docs ){
Console. log (docs );
Db. close ();
});
});
}
});
Db. on ("close", function (err, db) {// close the database
If (err) throw err;
Else console. log ("database closed successfully .");
});

Close DatabaseDb. close ([forceClose], [callback]);

When forceClose is true, the database is forcibly disabled. When the database is closed, you cannot use open to enable the database.

When forceClose is set to false, the database is not forcibly closed. After the database is closed, open the database again.

When foreClose is true:

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = new mongo. Server (host, port, {auto_reconnect: true}); // the server on which the database is created
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true}); // create a database object
Db. open (function (err, db) {// connect to the database
If (err)
Throw err;
Else {
Db. collection ("users", function (err, collection ){
Collection. insert ({username: "panpan", firstname: "Li"}, function (err, docs ){
Console. log (docs );
Db. close (false );
});
});
}
});
Db. once ("close", function (err, db) {// close the database
If (err) throw err;
Else {
Db. open (function (err, db ){
Db. collection ("users", function (err, collection ){
Collection. insert ({username: "3", firstname: "Zhang"}, function (err, docs ){
If (err) throw err;
Else {
Console. log (docs );
Db. close (true );
}
})
});
});
}
});

//Read data

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = mongo. Server (host, port, {auto_reconnect: true });
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true });
Db. open (function (err, db ){
Db. collection ("users", function (err, collection ){
If (err) throw err;
Else {
Collection. find ({}). toArray (function (err, docs ){
If (err) throw err;
Else {
Console. log (docs );
Db. close ();
}
});
}
});
});

// Search with query Conditions

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = mongo. Server (host, port, {auto_reconnect: true });
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true });
Db. open (function (err, db ){
Db. collection ("users", function (err, collection ){
If (err) throw err;
Else {
Collection. find ({username: {$ in: ["Yansi", "3"]}). toArray (function (err, docs ){
If (err) throw err;
Else {
Console. log (docs );
Db. close ();
}
});
}
});
});

//Insert a batch of dataAnd search for type = food and the price field value is less than 10

The Code is as follows:

Var mongo = require ("mongodb ");
Var host = "localhost ";
Var port = mongo. Connection. DEFAULT_PORT;
Var server = mongo. Server (host, port, {auto_reconnect: true });
Var db = new mongo. Db ("node-mongo-examples", server, {safe: true });
Var docs = [
{Type: "food", price: 11 },
{Type: "food", price: 10 },
{Type: "food", price: 9 },
{Type: "food", price: 8 },
{Type: "book", price: 9}
];
Db. open (function (err, db ){
Db. collection ("goods", function (err, collection ){
If (err) throw err;
Else {
Collection. insert (docs, function (err, docs ){
If (err) throw err;
Else {
Collection. find ({type: "food", price: {$ lt: 10}). toArray (
Function (err, docs ){
If (err) throw err;
Else {
Console. log (docs );
Db. close ();
}
}
);
}
})
}
});
});

Expression of or in the query:

The Code is as follows:

Collection. find ({$ or :[
{Type: "food "},
{Price :{$ lt: 10 }}
]})

About node. the introduction of js operations on mongoDB databases will come here today. Basically, common operations are provided with examples. If it is more complicated, let's take full advantage of it. We will continue to explain it if we have the opportunity.