What is Database?

Hello everyone, lets start with basic Database overview:

What is Database? Why use Database?

◈   Databases are systems that allow users to store and organize large amount of data.

◈   They are useful when dealing with large amounts of data.

Typical Users who use Database

Database have wide veriety of users!

◈   Analysts :

-     Marketing

-     Business

-     Sales

◈   Technical :

-     Data Scientist

-     Software Engineers

-     Web Developers

Basically anyone needing to deal with data has great use scale to use database!

From Spreadsheets to Databases

Most users have some familiarity with spreadsheet software (such as Excel). Let's discuss the use case for spreadsheets versus databases. We will have a look towards usecases of spreadsheets and usecases of Database, so that we can expand the knowledge of the same.

◈   Spreadsheets :

-     Spreadsheets are best to use when there is one-time analysis.

-     Also if there is quickly need to chart something out.

-     They work with reasonable data set size such as google sheet or excel sheet.

-     What really nice about spreadsheets is it allow the ability for untrained people to work with data.

◈   Databases :

-     Databases are best at Data Integrity (that means, it really dont allow anyone to click on the shell and change the data).

-     Databases can handle massive amount of data (in such amount where spreadsheet used to crash).

-     Databases can quickly combine different datasets.

-     Databases are also perfect for automating steps for re-use, with the help of SQL syntax, which we will learn later.

-     Databases can support data for websites and applications.

Database Platform Options

Database Platform	Description
PostgreSQL	FREE (Open Source). Widely used on internet. Multi platform.
MySQL / MariaSQL	FREE (Open Source). Widely used on internet. Multi platform.
MS SQL Server Express	FREE, but with some limitations. Compatible with SQL Server. Windows Only.
Microsoft Access	Cost. Not easy to use just SQL
SQLite	FREE (Open Source). Mainly command line

We will be focusing on the PostgreSQL, because PostgreSQL is free, it is multi platform i.e it can be used on MacOS, Windows or linux.. And reason behind why it is widely used is, it is easy to install and hit the ground running.

SQL

◈   SQL (Structured Query Language) is the programming language used to communicate with the Database.

-    PostGreSQL is a great Database choice for learning how to use SQL. SQL is all the thing we are going to learn in this course, it is the way by which we can communicate with database to get data out of it or put data into it. And SQL can be used in variety of Database platforms and softwares that use SQL.

◈   SQL Example :

     We will learn how to write and use SQL. So the general syntax of SQL will look something like this, some column names from the table and then we have some functions and clauses, here I'm ordering by the first_name.

in above example,

application_id, first_name, last_name are the column names of the table. Here table name is subscribers and order by is a clause