Below is the list of basic MONGO DB commands which a user can start with :
1) To list all the databases
show dbs
Example:
> show dbs
admin (empty)
local 0.078GB
mydb 0.078GB
2) To create a new database
use dbName
Example:
> use mydb
switched to db mydb
3) Check in the list of database that db created or not. Use cmd:
show dbs
Example:
> show dbs
admin (empty)
local 0.078GB
mydb 0.078GB
But your recently created db will not appear in the list until and unless you have not made any entry in it.
To do the entry in the database you created, hit the below cmd:
db.users.insert({'name':'shikha'})
Example:
> db.users.insert({'name':'shikha'})
WriteResult({ "nInserted" : 1 })
Then use the below command :
show dbs
Example:
Example:
> show dbs
admin (empty)
local 0.078GB
mydb 0.078GB
shikha 0.078GB
users 0.078GB
Now your created db is appearing in the list of dbs
4) To check currently which db you are using:
db
Example:
> db
users
5) To switch to one db to another db, use below cmd:
use yourDbName
Example:
> use user
switched to db user
6) To list all the collections of the current db, use the below command:
show collections
Example:
> show collections
system.indexes
users
7) To drop the database on which you currently are, use the below command:
db.dropDatabases()
Example:
> db.dropDatabase()
{ "dropped" : "users", "ok" : 1 }
8) To create a collection inside a db on which you are currently in, use below command:
db.createCollection("collectionName")
Example:
> db.createCollection("blog")
{ "ok" : 1 }
To create collection automatically just insert command with your collection name then mongo itself create a new collection.
like:
db.login.insert({'name': 'shikha', 'password': '123456'})
Example:
> db.login.insert({'name': 'shikha', 'password': '123456'})
WriteResult({ "nInserted" : 1 })
9) To drop a particular collection from the current db in use, hit the below cmd:
db.collectionName.drop()
Example:
> show collections
blog
login
system.indexes
> db.blog.drop()
true
10) To insert data in the particular collection, hit the below cmd:
db.login.insert({'name': 'shikha', 'password': '123456'})
Example:
> db.login.insert({'name': 'shikha', 'password': '123456'})
WriteResult({ "nInserted" : 1 })
To do the multiple entries at a single, hit use below cmd:
db.login.insert({'name': 'shikha', 'password': '123456'}, {'name': 'komal', 'password': '123456'})
Example:
> db.login.insert({'name': 'shikha', 'password': '123456'}, {'name': 'komal', 'password': '123456'})
WriteResult({ "nInserted" : 1 })
11) To find a result from the particular collection, use below cmd:
db.login.find({'name': 'shikha'})
Example:
> db.login.find({'name': 'shikha'})
{ "_id" : ObjectId("573473da41a5b179fd014327"), "name" : "shikha", "password" : "123456" }
To display the result in more readable way, use below cmd:
db.login.find({'name': 'shikha'}).pretty()
Example:
> db.login.find({'name': 'shikha'}).pretty()
{
"_id" : ObjectId("573473da41a5b179fd014327"),
"name" : "shikha",
"password" : "123456"
}
12) How to use of "or" in mongo?
Syntax with example:
db.login.find(
{
$or: [
{name: shikha}, {password:123456}
]
}
).pretty()
>db.login.find({$or: [{'name': 'lalit'},{'password':'123456a'} ]}).pretty()
{
"_id" : ObjectId("5734745141a5b179fd01432a"),
"name" : "lalit",
"password" : "123456a"
}
13) To list all the data of particular collection, hit below cmd:
db.login.find()
Example:
> db.login.find()
{ "_id" : ObjectId("5734739941a5b179fd014326"), "name" : "harneet", "password" : "123456" }
{ "_id" : ObjectId("573473da41a5b179fd014327"), "name" : "shikha", "password" : "123456" }
{ "_id" : ObjectId("5734742941a5b179fd014328"), "name" : "shikha2", "password" : "123456" }
{ "_id" : ObjectId("5734744241a5b179fd014329"), "name" : "shikha1", "password" : "123456" }
{ "_id" : ObjectId("5734745141a5b179fd01432a"), "name" : "lalit", "password" : "123456a" }
14) To update the data of the particular entry, hit below cmd:
db.login.update({'name':'komal'}, {$set:{'name':'mukul'}},{multi:true})
Example:
> db.login.update({'name':'lalit'}, {$set:{'name':'mukul'}},{multi:true})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
15) To remove a entry a from the collection data, hit the below cmd:
db.login.remove({'name':'nisha'})
Example:
> db.login.remove({'name':'shikha'})
WriteResult({ "nRemoved" : 1 })
16) To count the number of entries in the collection, hit the below cmd:
db.login.count()
Example:
> db.login.count()
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