Hwayeonniii

Reference 

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https://www.youtube.com/embed/HXV3zeQKqGY

SQL Basics 

Structured Query Language (SQL)

- SQL: a language used for interacting with Relational Database Management System (RDBMS)

1. You can use SQL to get the RDBMS to do things for you

• Create, retrieve, update & delete data
• Create & manage databases 
• Design & create database tables
• Perform administration tasks (security, user management, import/export, etc)

 2. SQL implementations vary between systems 

• Not all RDBMS’ follow the SQL standard to a ‘T' (Postgres, MySQL, Oracle, Microsoft SQL Server)
• The concepts are the same, but the implementation may vary

 3. SQL is actually a hybrid language, it’s basically 4 types of language in one

• Data Query Language (DQL)

·      Used to query the database for information

·      Get information that is already stored there

• Data Definition Language (DDL)

·      Used for defining database schemas

*Schemas: Overall layout of the database. 

ex > what columns those tables are going to have and the data types that those columns are going to be able to store 

• Data Control Language (DCL)

·      Used for controlling access to the data in the database

·      User & permissions management

• Data Manipulation Language (DML)

·      Used for inserting, updating, and deleting data from the database

Queries

• Query: a set of instructions given to the RDBMS, written in SQL that tell the RDBMS what information you want it to retrieve for you

·      TONS of data in a DB

·      Often hidden in a complex schema

·      Goal is to only get the data you need

SELECT employee.name, employee.age
FROM employee
WHERE employee.salary > 3000;

MySQL Mac Installation 

1.     Click https://dev.mysql.com/downloads/mysql/

2.     Download ‘DMG Archive’ > Click ‘No thanks, just start my download’ which is in the bottom of the next page

3.     Username: root, password: (set your own password) > follow the download instruction on Mac

4.     Open ‘terminal’ application 

5.     Type    mysql -u root -p 

6.     Type password

7.     Type create database giraffe; 

*giraffe is the name of the database: you can use another name

8.     Click https://popsql.com

9.     Sign up with google account and download the app

*PopSQL connect MySQL database server that we have set up 

10.  Go to the link: app.popsql.com

11.  Click ‘PopSQL’ > Click ‘Manage Connection’

12. Connection name: mysql / Hostname: localhost / Database: giraffe / username: (your username), password: (your password)