suppose you have correctly installed the mongodb, and opened a shell like this: zhang@linux:~$ mongo MongoDB shell version: 2.0.4 connecting to: test > first of all, let’s show all the dbs: zhang@linux:~$ mongo MongoDB shell version: 2.0.4 connecting to: test > show dbs local (empty) > then let’s use one of it, we can switch between dbs use: > show dbs local (empty) > use local switched to db local > someone may ask, how to create a database then ? yeah, good question !
In Mysql we can use “create database Name;” to create a database, but, MongoDB didn’t provides any command to create database, Actually, we don’t need to do it ! Look ! we just defined a database by command “use mydatabase”, which is not created yet > use mydatabase switched to db mydatabase > show dbs local (empty) > MongoDB create it when we first save value into it > db.colcase.save( {testcase:”hello”} ) > show dbs local (empty) mydatabase 0.0625GB > show collections colcase system.indexes > db.colcase.find() { “_id” : ObjectId(“513fe233aac1372ab215f350”), “testcase” : “hello” } > P.S MongoDB created the “colcase” collection and the “mydatabase” database automatically when we first save value into it.