Database (Base de données) and SQL

Base de données (Database)

• A foreign key is a column whose values reference a primary key in another table.
• A primary key in SQL is a column or set of columns with unique values for each row in a table.
• An intermediary table results from a Many-To-Many association between two entities, linking two tables.
• Data model design models used in MERISE include:
  • Conceptual Data Model (MCD)
  • Logical Data Model (MLD)
  • Physical Data Model (MPD)

SQL

• A SQL join combines rows from two tables based on a common condition.
• SQL join types:
  • INNER JOIN
  • LEFT JOIN
  • RIGHT JOIN
  • FULL OUTER JOIN
  • CROSS JOIN
• To select distinct values from a column: SELECT DISTINCT column FROM table;
• A subquery in SQL is nested within another query.
• To calculate the sum of a column's values: SELECT SUM(column) FROM table;
• To get the number of rows in a table: SELECT COUNT(*) FROM table;
• To check for NULL values in a column: SELECT * FROM table WHERE column IS NULL
• To select rows from a table where a column's value exceeds 100: SELECT * FROM table WHERE column > 100;
• To limit the number of results returned by a SQL query to 10: SELECT * FROM table LIMIT 10;

RGPD (GDPR)

• GDPR (General Data Protection Regulation) is EU regulation designed to protect individuals' personal data and strengthen privacy and security rights.
• GDPR's main objectives:
  • Protect individual's personal data
  • Harmonize data protection regulations across the EU.
• Data portability under GDPR allows individuals to receive their personal data in a structured, commonly used, machine-readable format and transmit it to another data controller.
• Key roles defined by GDPR:
  • Data controller
  • Data processor
  • Data Protection Officer (DPO).

API

• A REST API (Representational State Transfer) uses HTTP verbs and specific conventions for operations.
• An API enables communication between two applications; for example, using the Google Maps API to integrate maps into an application.
• To make a GET request with a REST API in Python:

  import requests
  url = 'https://api.example.com/resource' 
  response = requests.get(url)
  

JSON/API

• A JSON (JavaScript Object Notation) response is a lightweight, human-readable data format.

JSON/Python

• To extract data from a JSON response in Python:

  import requests
  url = 'https://api.example.com/resource'
  response = requests.get(url)
  data = response.json()