http://fabienvauchelles.github.io/stweb-mongodb

1. MONGODB

2. INTRODUCTION

3. WHAT IS MONGODB ?
MongoDB is :
a document store,
distributed,
and using JSON.

4. ABOUT MONGODB
2007 : Creation
2010 : First version
2015 : MongoDB 3.0

5. BASICS

6. ARCHITECTURE

7. JSON FORMAT
{
'name':'I’mastring'
'number':12
'array_of_string':['bernard','joe']
}

8. INSTALLATION
All instructions are on .MongoDB website

9. CMD / SERVER
Open a shell and start the server :
$mongod

10. CMD / IMPORT
IMPORT THE DATASET
https://raw.githubusercontent.com/fabienvauchelles/stweb‐
mongodb/master/data/clients.json
IMPORT IN MONGODB
In a new shell :
$mongoimport--dbmyapp--collectionclients--jsonArray--fileclients.json

11. CMD / START
Start the command line client :
$mongo

12. CMD / DATABASES
Show databases :
$showdbs
Use a specific database :
$usemyapp
Show collections :
$showcollections

13. CMD / FIND
Show one document of a collection :
db.users.findOne()
Show all documents of a collection, without formatting :
db.users.find()
Show all documents of a collection, with formatting :
db.users.find().pretty()

14. C(R)UD

15. SYNTAX
db.<collection>.<command>

16. INSERT A DOCUMENT
Insert 3 documents :
db.users.insert({name:"Grumpy",country:"France",age:2,gender:"M"})
db.users.insert({name:"Lizzy",country:"USA",age:1,gender:"F"})
Get the document :
db.users.findOne({name:"Grumpy"})
The _id field is a unique key (type: ObjectId)

17. REMOVE A DOCUMENT
db.users.insert({name:"Samy",country:"DK",age:3,gender:"M"})
db.users.remove({name:"Samy"})

18. REPLACE A DOCUMENT BY ANOTHER
Update all fields of 1 document :
db.users.update({name:"Grumpy"},{name:"Sleepy"})
Get the document :
db.users.findOne({name:"Grumpy"})
db.users.findOne({name:"Sleepy"})
One document, with only field name !

19. UPDATE ONLY 1 FIELD OF A
DOCUMENT
Update 1 field of 1 document :
db.users.update({name:"Lizzy"},{$set:{country:"Russia"}})
Get the document :
db.users.findOne({name:"Lizzy"})

20. UPDATE MULTIPLE DOCUMENTS
Insert 3 documents :
db.users.insert({name:"Bernard"})
db.users.insert({name:"Bernard"})
db.users.insert({name:"Bernard"})
Update the first matching document :
db.users.update({name:"Bernard"},{$set:{name:"Sarah"}})
db.users.find({name:"Bernard"})
Update all documents :
db.users.update({name:"Bernard"},{$set:{name:"Sarah"}},{multi:true})
db.users.find({name:"Bernard"})
db.users.find({name:"Sarah"})

21. ADD AN ITEM AT THE END OF AN
ARRAY
Insert 1 document with an array :
db.users.insert({name:"Marty",hobbies:["hates","loves"]})
db.users.findOne({name:"Marty"})
Add an item at the end of an array :
db.users.update({name:"Marty"},{$push:{hobbies:"fishing"}})
db.users.findOne({name:"Marty"})

22. REMOVE LAST ITEM OF AN ARRAY
db.users.update({name:"Marty"},{$pop:{hobbies:1}})
db.users.findOne({name:"Marty"})

23. REMOVE 1 ITEM OF AN ARRAY
db.users.update({name:"Marty"},{$pull:{hobbies:"hates"}})
db.users.findOne({name:"Marty"})

24. ADD AN ITEM IN THE ARRAY IF IT
DOES NOT ALREADY EXIST
db.users.update({name:"Marty"},{$addToSet:{hobbies:"cycling"}})
db.users.update({name:"Marty"},{$addToSet:{hobbies:"cycling"}})
db.users.findOne({name:"Marty"})

25. ADVANCED SEARCH

26. LOGICAL OPERATOR / $AND
$and is implied.
All women, from Russia, 50 yo :
db.clients.find({$and:[
{gender:"F"},
{country:"Russia"},
{age:50}
]})
is equals to :
db.clients.find({
gender:"F",
country:"Russia",
age:50
})

27. LOGICAL OPERATOR / $OR
All women OR from Russia OR 50 yo :
db.clients.find({$or:[
{gender:"F"},
{country:"Russia"},
{age:50}
]})

28. COMPARISON OPERATORS / $LT & $LTE
All clients with less or equals than 8 years :
db.clients.find({age:{$lte:8}})

29. COMPARISON OPERATORS / $GT & $GTE
All clients with more than 76 years (strictly) :
db.clients.find({age:{$gt:76}})

30. $EXISTS FIELD OPERATOR
All clients with have filled their age :
db.clients.find({age:{$exists:true}})

31. ARRAY OPERATOR / $ALL (AND)
db.users.insert({name:"John",hobbies:["auto","game"]})
db.users.insert({name:"Nicolas",hobbies:["game"]})
All users who practices "auto" AND "game" :
db.users.find({hobbies:{$all:["auto","game"]}})

32. ARRAY OPERATOR / $IN (OR)
All users who practices "auto" OR "game" :
db.users.find({hobbies:{$in:["auto","game"]}})

33. SORT
All clients, sorted by ascending country and descending name :
db.clients.find().sort({country:1,name:-1})
1 = Ascending order
‐1 = Descending order

34. COUNT
To count the number of occurrences replaces find by count :
db.clients.find({age:{$gt:76}})
becomes :
db.clients.count({age:{$gt:76}})

35. AGGREGATES

36. PIPE
Mongos aggregates is a pipe of operations.
EXAMPLE
I want the count of young people (20‐30) for each city :

37. SYNTAX
db.<collection>.aggregate([{$op-1},{$op-2},..,{$op-n}])

38. FILTERS / $MATCH
Same filter that is used in find, update, etc.
db.clients.aggregate([
{$match:{age:{$gt:70}}}
])

39. PROJECTIONS / $PROJECT
$project chooses returned fields.
db.clients.aggregate([
{$project:{name:1}}
])
Remark: by default, _id is always in the projection and other
fields are not.

40. DUPLICATES / $UNWIND
$unwind repeats a document for each item of an array.
db.users.insert({name:"Sam",hobbies:["cycle","boat","computer"]})
db.users.aggregate([
{$match:{name:"Sam"}},
{$unwind:"$hobbies"}
])

41. GROUPS ($GROUP)
$group is SQL group by.
$group performs operations on similar documents
Operations: $sum, $avg, $first, $last, $min, $max, $push,
$addToSet
db.clients.aggregate([
{$group:{_id:"$country",maxage:{$max:"$age"}}}
])
db.clients.aggregate([
{$group:{_id:"$country",maxage:{$max:"$age"}}},
{$sort:{_id:1}},
{$project:{_id:0,country:"$_id",maxage:1}}
])

42. OTHERS OPERATIONS
There is other operations : $sort, $limit, $skip, etc.
is your friend !MongoDB documentation

43. © Fabien Vauchelles (2015)
GO FURTHER
MongoDB University