Creating, Listing, and Deleting Databases Example

To help solidify the database operations, Listing 13.3 illustrates the full process of creating, listing, and deleting databases. A connection is made to the MongoDB server, and then lines 4–7 list the current databases. Then lines 8 and 9 create a new database by calling create-Collection(). Inside the createCollection() callback handler, the databases are listed again to verify creation.

Lines 15–32 delete the database by using dropDatabase(). Notice that inside the drop-Database() callback, a setTimeout() timer is implemented to wait for a number of seconds before checking the list of databases to verify that the database was deleted. The output is shown in Figure 13.3.

Listing 13.3 db_create_list_delete.js: Creating, listing, and deleting databases, using the MongoDB Node.js driver

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01 var MongoClient = require('mongodb').MongoClient;
02 MongoClient.connect("mongodb://localhost/", function(err, db) {
03   var adminDB = db.admin();
04   adminDB.listDatabases(function(err, databases){
05     console.log("Before Add Database List: ");
06     console.log(databases);
07   });
08   var newDB = db.db("newDB");
09   newDB.createCollection("newColleciton", function(err, collection){
10     if(!err){
11       console.log("New Database and Collection Created");
12       adminDB.listDatabases(function(err, databases){
13         console.log("After Add Database List: ");
14         console.log(databases);
15         db.db("newDB").dropDatabase(function(err, results){
16           if(!err){
17             console.log("Database dropped.");
18             setTimeout(function() {
19               adminDB.listDatabases(function(err, results){
20                 var found = false;
21                 for(var i = 0; i < results.databases.length; i++) {
22                   if(results.databases[i].name == "newDB") found = true;
23                 }
24                 if (!found){
25                   console.log("After Delete Database List: ");
26                   console.log(results);
27                 }
28                 db.close();
29               });
30             }, 15000);
31           }
32         });
33       });
34     }
35   });
36 });

Figure 13.3 Creating, listing, and deleting databases using the MongoDB Node.js driver.