MySQL : Structured Query Language

The acronym SQL stands for Structured Query Language
SQL is the standard language for data manipulation
SQL is the standard language for relational database management.

Three Main Uses of SQL are :
Read ,Write , Update



SQL is used for many things; however, Data Retrieval  was stressed as THE MAIN THING used by Data Scientist





Data Scientist might do a little of the analysis using SQL, however the main thing they're using SQL for is data retrieval.



Learning Objective:

Explain why thinking before coding is important 

Explain why it is important to understand how data in a database is relate to each other 

Describe what a database is 

Think before you do:

  What is the problem you are trying to do..?

   

How this help ..?

It produce accurate result 
Speed up your work
Have Less Rework
 


what is database ..?
 A container that is used to write all the file and store all the data 
If you think of this, in real world terms, it'd be like a filing system that has many cabinets all along the wall that contains and organizes all the data

Data Models, Part 2: The Evolution of Data Models:

The data model scheme of organization should always represent the real world as closely as possible.


Advantages of Relational database are :
  •   It allows you to write data to it 
  •   It allows you to retrieve and update data
  •   It simplifies the connections between the data
  •   It allows you to easily write queries against it
SQL IN A BIG DATA MODEL:


RELATIONAL VS TRANSACTIONAL:


Relational model  Used to optimize querying data, making it easy and intuitive to access the data,Shows the relationships between the different tables

Transactional model It's an operational database 







Retrieving Data with a SELECT Statement:









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