MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas.
to start server (mongod is mongo deamon)
mongod
to start shell
mongo
show dbs;
create/use database
Change database
use db_name;
show current database
db;
Collections are similar to table
show collections;
db.createCollection("students");
Drop collection/table
db.students.drop();
drop database
db.dropDatabase();
insertOne
db.students.insertOne({_id: 1, name: "shailesh"});
insertMany
db.students.insertMany([{_id: 2, name: "bagde"}, {_id: 3, name: "sheldon"}]);
count document
db.students.count();
select all documents/records
db.students.find();
select with projection
db.students.find({},{_id: 0});
db.students.find({},{name:0});
exists operator
db.students.find({age: {$exists: false}});
COMPARISON OPERATORS
in operator
db.students.find({_id: {$in: [2,3]}});
not equal operator
db.students.find({_id: {$ne: 2}});
equal operator
db.students.find({_id: {$eq: 2}});
less than $lt
less than equal $lte
greather than $gt
greater than equal $gte
LOGICAL OPERATORS
$and operator
db.students.find({$and : [{_id : {$gt:1}}, {_id: {$lt: 4}}]})
$or operator
db.students.find({$or : [{name : "bagde"}, {name: "shailesh"}]})
like case insensitive
db.students.find({name: /h/i})
exact match
db.students.find({name: /^BagDe$/i})
UPDATE
db.students.updateOne({_id: 1}, {$set : {age: 23}});
db.students.updateMany({age : {$exists: false}}, { $set : {age : 25}})
db.students.updateMany({}, {$set: {address: {city: "Mumbai", state: "MH"}}})
db.students.updateOne({_id: 4}, { $set : {address : {city: "Nagpur"}}});
Unset/Delete Fields
db.students.updateMany({}, {$unset : {city: ""}});
search within sub document
db.students.find({"address.city" : "Nagpur"}).pretty();
Delete Records
db.students.deleteOne({ $or : [{ age : {$lt : 25}}, {name : "sheldon"}] })
DISTINCT
db.students.distinct(“city”)
ORDER BY
db.students.find().sort({name: -1})
LIMIT
db.students.find().limit(10)
db.students.find().skip(5).limit(10)
Aggregation
Aggregate on all documents
db.emps.aggregate([{$group: {
_id : null,
total : {$sum : "$salary"},
average : {$avg: "$salary"},
min : {$min: "$salary"},
max : {$max: "$salary"},
count : {$sum: 1}
}}]).pretty()
Aggregate on group by address
db.emps.aggregate([{$group: {
_id : { address: "$address" },
total : {$sum : "$salary"},
average : {$avg: "$salary"},
min : {$min: "$salary"},
max : {$max: "$salary"},
count : {$sum: 1}
}}]).pretty()
ForEach Map
db.emps.find().forEach(x => { print(x.name) })
db.emps.find({salary: { $exists: -1 } }, {"salary": 1, _id: 0}).map(x => x.salary * 0.10)
MongoDB Assignment for Practice
var docs = [ {"name":"neha","contact_number":"9833910534","address":"mumbai","salary":30000,"employee_id":98821,"role":"manager"}, {"name":"mina","contact_number":"9833910535","address":"thane","salary":32000,"employee_id":98823,"role":"sales"}, {"name":"pankaj","contact_number":"9833910536","address":"bhopal","salary":40000,"employee_id":98824,"role":"hr"}, {"name":"mareena","contact_number":"9833910537","address":"meerut","salary":45000,"employee_id":98825,"role":"support"}, {"name":"pooja","contact_number":"9833910538","address":"delhi","salary":50000,"employee_id":98826,"role":"developer"}, {"name":"namita","contact_number":"9833910539","address":"surat","salary":52000,"employee_id":98820,"role":"sales"}, {"name":"sneha","contact_number":"9833910510","address":"baroda","salary":55000,"employee_id":98827,"role":"support"}, {"name":"anjali","contact_number":"9833910511","address":"ahmedabad","salary":60000,"employee_id":98828,"role":"tester"}, {"name":"harsha","contact_number":"9833910512","address":"mumbai","salary":20000,"employee_id":98829,"role":"operations"}, {"name":"varun","contact_number":"9833910512","address":"mehsana","salary":56000,"employee_id":98831,"role":"tester"}, {"name":"preeti","contact_number":"9833910513","address":"noida","salary":87000,"employee_id":98832,"role":"developer"}, {"name":"madhu","contact_number":"9833910525","address":"bangalore","salary":22000,"employee_id":98833,"role":"sales"} ]; db.createCollection("emps"); db.emps.insertMany(docs); db.emps.find();
var docs = [{“name”:”neha”,”contact_number”:”9833910534″,”address”:”mumbai”,”salary”:30000,”employee_id”:98821,”role”:”manager”},{“name”:”mina”,”contact_number”:”9833910535″,”address”:”thane”,”salary”:32000,”employee_id”:98823,”role”:”sales”},{“name”:”pankaj”,”contact_number”:”9833910536″,”address”:”bhopal”,”salary”:40000,”employee_id”:98824,”role”:”hr”},{“name”:”mareena”,”contact_number”:”9833910537″,”address”:”meerut”,”salary”:45000,”employee_id”:98825,”role”:”support”},{“name”:”pooja”,”contact_number”:”9833910538″,”address”:”delhi”,”salary”:50000,”employee_id”:98826,”role”:”developer”},{“name”:”namita”,”contact_number”:”9833910539″,”address”:”surat”,”salary”:52000,”employee_id”:98820,”role”:”sales”},{“name”:”sneha”,”contact_number”:”9833910510″,”address”:”baroda”,”salary”:55000,”employee_id”:98827,”role”:”support”},{“name”:”anjali”,”contact_number”:”9833910511″,”address”:”ahmedabad”,”salary”:60000,”employee_id”:98828,”role”:”tester”},{“name”:”harsha”,”contact_number”:”9833910512″,”address”:”mumbai”,”salary”:20000,”employee_id”:98829,”role”:”operations”},{“name”:”varun”,”contact_number”:”9833910512″,”address”:”mehsana”,”salary”:56000,”employee_id”:98831,”role”:”tester”},{“name”:”preeti”,”contact_number”:”9833910513″,”address”:”noida”,”salary”:87000,”employee_id”:98832,”role”:”developer”},{“name”:”madhu”,”contact_number”:”9833910525″,”address”:”bangalore”,”salary”:22000,”employee_id”:98833,”role”:”sales”}];
- show employees in descending order – salary
- show all employees from Mumbai
- show all employees having salary more 50000
- show sum of salary from emps collection
- show all distinct address
- show names of employees having max salary
- show employees having 2nd highest salary
- count employees from mumbai only
- show all female employees
- show all male employees