workbook_notes.txt

Q9

tables 

rows

attributes

datatypes dependent on the type of rdbms, in postgres you have bigint, text, varchar etc

how do you format the db in rails? migrations

constraints 

tables can relate to each other through their attributes

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Q10

https://en.wikipedia.org/wiki/Data_integrity

data integrity in a relational db is data being accurate and consistent

you use things like validators in rails for user input to ensure that no bad data is stored in a db

some of the things that enforce consistency are:

primary keys, the value is always unique, it can be an auto incrementing number, uuids

foreign keys, attributes that we have in our records that connect different tables together, refers to a primary key value 

columns are for each specific table 

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Q11

the way in which we can manipulate records in a relational database model is through SQL

SQL definiton 

the way in which we can add records to a relational db is through the INSERT INTO command etc

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https://stackoverflow.com/questions/2307283/what-does-olog-n-mean-exactly

Q12

O(n log n)

quicksort

mergesort

bubblesort

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Q13

binary search O(log n)

linear search O(n)

[1,2,3].each do |num|
  if num == 2
    return num
  end 
end

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Q14

a.

software https://stackshare.io/airbnb/airbnb

b.

hardware 

make some assumptions

they're using amazon EC2 which is a cloud offering for running virtual machines

the hardware that the virtual machines is running on is a server in an amazon data center

c.

when we deploy the web server code is always running on a virtual machine

if you were using continuous deployment you could update your code an any time

rails controller, how that connects to the database

how is sass or js compiled by rails

the client side is sending http requests to our rails app, our rails app is sending back http responses

d.

airbnb uses a relational db

the data would be structured into different tables

and each table would contain a number of rows 

document db => the data would structured into collections with individual documents nested in these collections

e. 

users

profiles

homes

locations

invoices

categories

payments

f. 

users have many homes

user has one profile

homes have one location

homes have many invoices

home has many categories

category has many homes

g. 

https://dbdiagram.io/

make a diagram

take a screenshot and put it into your submission