MongoDB

mongodb

MongoDB is an open-source document database and leading NoSQL database.

It is written in C++.

It is a cross-platform.

Document oriented data based.

that provides, high performance, high availability, and easy scalability.It works on concept of collection

and document.

Basic syntax of use DATABASE statement is as follows −

.use DATABASE_NAME 

use music

Your created database (mydb) is not present in list.

To display database, you need to insert at least one document into it.

db.movie.insert({"name":" songdetails"})


MongoDB db.dropDatabase() command is used to drop a existing database.

db.dropDatabase()

To check the list of available databases by using the command, show dbs.

>show dbs
local      0.78125GB
mydb       0.23012GB
test       0.23012GB

MongoDB db.createCollection(name, options) is used to create collection.

db.createCollection(name, options)

MongoDB's db.collection.drop() is used to drop a collection from the database.

db.COLLECTION_NAME.update(SELECTION_CRITERIA, UPDATED_DATA)

Example:

1) Create a Database called music​.

• use music

2) Create a collection called songdetails​.

• db.createCollection("songdetails")

3) Create the above 5 song documents.

db.songdetails.insert({"Song Name":"Thaniye Thananthaniye","Film":"Rhythm","Music Director":"A.R.Rahman","Singer":"Shankar mahadevan"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Evano Oruvan","Film":"Alai Payuthey","Music Director":"A.R.Rahman","Singer":"Swarnalatha"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Roja Poonthottam","Film":"Kannukkul Nilavu","Music Director":"Ilaiyaraja","Singer":"Unnikirishnan,Anuradha Sriram"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Vennilave Vennilave vinnaithandi","Film":"Minsara Kanavu","Music Director":"A.R.Rahman","Singer":"Hariharan,Sadhana Sargam"})

WriteResult({ "nInserted" : 1 })

db.songdetails.insert({"Song Name":"Sollamal Thottu Chellum Thendral","Film":"Dheena","Music Director":"Yuvan Shankar Raja","Singer":"Hariharan"})

4) List all documents created.

• db.songdetails.find().pretty()

5) List A.R.Rahman’s songs.

• db.songdetails.find({"Music Director":"A.R.Rahman"})

6) List A.R.Rahman’s songs sung by Unnikrishnan.

• db.songdetails.find({"Music Director":"Ilaiyaraja","Singer":"Unnikirishnan,Anuradha Sriram"},{"Song Name":1,_id:0})

7) Delete the song which you don’t like.

• db.songdetails.remove({"Song Name":"Evano Oruvan"})

8) Add new song which is your favourite.

• db.songdetails.insert({"Song Name":"Kannana Kanne","Film":"Viswasam","Music Director":"D.imman","Singer":"Sid Sriram"})

9) List Songs sung by Sid sriram from Viswasam film.

• db.songdetails.find({"Film":"Viswasam","Singer":"Sid Sriram"},{"Song Name":1,_id:0})

10)List out the singers’ names in your document.

• db.songdetails.find({},{"Singer":1,_id:0}).pretty()

example2

1) Create a Database called student

use student

2) Create a collection called ​studentmarks

db.creatCollection(“studentmarks”)

3) Create the documents listed in above table.

db.songdetails.insert({"name":"Malal","maths_marks":45,"english_marks":53,"science_marks":72})

.

.

.

4) Increase the maths marks of Mala by 6 marks

5) List the names of students who got more than 50 marks in Maths Subject.

6)Add a new column(field) for Average for all students.

db.studentmarks.aggregate({$addFields:{“avarage”:””}}).pretty()              

7) Update Marks_Science=75 to Lucky .

db.studentmarks.update({“name”:”Lucky”},{$set:{science_marks”:75}})

8) List the names who got more than 50 marks in all subjects.

db.studentmarks.find({$and:[{"english_marks":{$gt:50}},{"science_marks":{$gt:50}},{"maths_marks":{$gt:50}}]},{"name":1,_id:0})

9) List the names who got less than 50 marks in Maths subject and more than 50 marks in English

db.studentmarks.find({$and:[{"english_marks":{$gt:50}},{"maths_marks":{$lt:50}}]},{"name":1,_id:0})

10) List the names who got less than 40 in both Maths and Science.

db.studentmarks.find({$and:[{"science_marks":{$lt:40}},{"maths_marks":{$lt:40}}]},{"name":1,_id:0})

11) Remove Science column/field for Raam

db.studentmarks.update({"name":"Raam"},{$unset:{"science_marks":88}})

12) Update John’s Math mark as 87 and English mark as 23, if john not available upsert.

db.studentmarks.insert({"name":"John","maths_marks":87,"english_marks":23})

13) Rename the english_marks column/field for John to science_marks

db.studentmarks.update({"name":"John"},{$rename:{"english_marks":"science_marks"}})

14) Remove Kumaran’s document from collection

db.studentmarks.remove({"name":"Kumaran"})

15) Find Kala’s or Aruli’s math_marks and science_marks

db.studentmarks.find({"name":"Aruli"},{"maths_marks":1,"science_marks":1}).pretty()