1.
Document Oriented
Databases
Lab
Ciao
ciao
Vai a fare
ciao ciao
Dr. Fabio Fumarola

2.
MongoDB
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3.
MongoDB with Docker
• Download docker images:
– https://registry.hub.docker.com/_/mongo/
• Run Mongo:
– docker run --name mongo -d -p 27017:27017 mongo
• Connect to Mongo:
– docker exec -it mongo bash
• Connect via robomongo:
– http://robomongo.org/
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4.
Mongodb Fundamentals
4

5.
Starting Mongo
• Asking for help:
– help
5

6.
Import same data
• curl -L http://j.mp/OSCONvenues | mongoimport -d
conf -c venues
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7.
Example of object
7
var place1 = {
"name" : "10gen HQ",
"address" : "578 Broadway 7th Floor",
"city" : "New York",
"zip" : "10011",
"tags" : [ "business", "awesome" ]
}

8.
Insert
>use places
>db.places.insert(place1)
It returns: WriteResult({ "nInserted" : 1 })
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9.
Querying
> db.places.find()
•Specify equality conditions
> db.places.find({ zip: "10011",
tags: "awesome" })
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{ "_id" : ObjectId("555473fb37abe83242ddd405"),
"name" : "10gen HQ",
"address" : "578 Broadway 7th Floor",
"city" : "New York", "zip" : "10011",
"tags" : [ "business", "awesome" ]
}

10.
Nested Documents
10
var place2 = {
"name" : "10gen HQ",
"address" : "578 Broadway 7th Floor",
"city" : "New York",
"zip" : "10011",
"tags" : [
"business",
"awesome"
],
"comments" : [
{
"date" : ISODate("2014-10-01T00:00:00Z"),
"author" : "Fabio",
"text" : "best place"
}
]
}

11.
Querying Nested Documents
• Find by specifying author
– db.places.find({"comments.author" : "Fabio"})
• Greater Than Operator ($gt):
– db.places.find({"comments.score" : { $gt: 20}})
• Less Than Operator ($lt)
– db.places.find({"comments.score" : { $lt: 20}})
– db.places.find({"comments.score" : { $lt: 40}})
• Conditions can be logically combined
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12.
Logical Combination
• Logical AND
– db.places.find({ "name" : "10gen HQ", "comments.author" : "Fabio" })
– db.places.findOne({ "name" : "10gen HQ", "comments.author" :
"Fabio" })
• Logical OR
– db.places.find({ $or : [{ "name" : "10gen HQ" }, {"comments.author" :
"Fabio" }]})
12

13.
Sort
• to sort by and the corresponding sort type:
– e.g. 1 for ascending
– and -1 for descending.
• Example:
– db.places.find().sort({"name" : 1, "comments.score" : -1})
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14.
Updating
• We can use the update() method to update
documents of a collection. The method accepts as its
parameters:
– a filter document to match the documents to update,
– an update document to specify the modification to
perform, and
– an options parameter (optional).
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15.
Update
15
db.places.update(
{name : "10gen HQ"},
{ $push :
{ comments :
{ author : "steve",
date : 6/26/2015,
text : "Office hours are great!"
}
}
}
)

16.
Update Multi
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db.places.update(
{name : "10gen HQ"},
{ $push :
{ comments :
{ author : "steve",
date : 6/26/2015,
text : "Office hours are great!"
}
}
},
{ multi: true}
)

17.
Remove
• We can use the remove() method to remove
documents from a collection.
• The method takes a conditions document that
determines the documents to remove.
• To specify a remove condition,
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18.
Remove Example
db.places.remove({"name" : "10gen HQ"})
db.places.remove({"name" : "10gen HQ"}, { justOne:
true } )
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19.
Drop Collections and DB
• The drop() method to drop a collection, including any
indexes
– db.places.drop()
• Drop a db
– use test
– db.dropDatabase()
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20.
Advanced Operations
20

21.
Regular Expression
21
// Regular Expressions
> db.posts.find({'comments.author': /^Fa/}){ _id :
ObjectId("4c4ba5c0672c685e5e8aabf3"),
name : "10gen HQ", address : "578 Broadway 7th Floor", city :
"New York",
zip : "10011",
comments : [ {
author : ”Fabio",
date : "Sat Apr 25 2010 20:51:03",

22.
Cursor
• How to get a cursor:
– var it = db.venues.find()
• Methods
– next
– hasNext
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23.
Aggregation
• Group Documents by a Field and Calculate Count
23
db.venues.aggregate(
[
{ $group: { "_id": "$location.city", "count": { $sum: 1 } } }
]
)

24.
Indexes
• By default index on collections are only on the _id
• the createIndex() method is used to create an index on a
collection
• Indexes can support the efficient execution of queries.
– For an ascending index type, specify 1 for <type>.
– For a descending index type, specify -1 for <type>.
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25.
Create Index
25
{
"createdCollectionAutomatically" :
false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
db.venues.createIndex({"country": 1})

26.
Create a Compound Index
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db.venues.createIndex({"country": 1, "distance": -1})
{
"createdCollectionAutomatically" :
false,
"numIndexesBefore" : 2,
"numIndexesAfter" : 3,
"ok" : 1
}
Upon successful index creation, the "numIndexesAfter"
value is one greater than the "numIndexesBefore" value.

27.
Geospatial Index
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db.venues.ensureIndex({ "location.geo": "2d" })
db.venues.find(
{"location.geo":{$near:[-122.6600248120735,45.5302342677652]}})
db.venues.find( { "location.geo" :
{ $geoWithin :
{ $box : [ [ 0 , 0 ] ,
[ -122 , 48 ] ]
} } } )

28.
References
• http://docs.mongodb.org/manual/
• https://gist.github.com/df238517f06500fec317.git
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