Databases

• On a larger note we have two types of databases in terms of how they handle schema (structure)
  • Strict on Structure (Relational databases)
  • Minimal restrictions (NOSQL)
• Relational database:
  • Data is tabular in nature.
  • Each column has a field and each row is a record
  • In a database i can have multiple tables
  • Tables can have relations between them
• Relational database have a formal language which is based on standard (Strucutred Query Language)
• Each DBMS adopts the standard and create their own query language
  • orcale => pl/sql
  • SQL Server => t-sql
  • mysql
  • postgres
• SQL
  • Create:
    • create a books table
      “`sql

    </ul>
    <h1>mysql</h1>
    CREATE TABLE books (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(255) NOT NULL,
    author VARCHAR(100) NOT NULL,
    description TEXT
    );
    <h1>microsoft sql server</h1>
    CREATE TABLE books (
    id INT IDENTITY(1,1) PRIMARY KEY,
    title VARCHAR(255) NOT NULL,
    author VARCHAR(100) NOT NULL,
    description TEXT
    );
    <h1>mysql</h1>
    INSERT INTO books (title, author, description) VALUES
    ('The Great Gatsby', 'F. Scott Fitzgerald', 'A novel set in the Roaring Twenties.'),
    ('To Kill a Mockingbird', 'Harper Lee', 'A novel about racial injustice in the Deep South.');
    <h1>microsoft sql server</h1>
    INSERT INTO books (title, author, description) VALUES
    ('The Great Gatsby', 'F. Scott Fitzgerald', 'A novel set in the Roaring Twenties.'),
    ('To Kill a Mockingbird', 'Harper Lee', 'A novel about racial injustice in the Deep South.');
    <code>* Retrieve</code>sql
    SELECT * FROM books;
    SELECT title, author FROM books;
    SELECT * FROM books WHERE author = 'Harper Lee';
    SELECT * FROM books ORDER BY title ASC;
    </li>
    </ul>
    <code>* Update</code>sql
    UPDATE books
    SET description = 'A classic American novel set in the 1920s.'
    WHERE title = 'The Great Gatsby';
    <code>* Delete</code>sql
    DELETE FROM books WHERE id = 1;
    “`

    Relational Database for Library

    

    ORM (object relational mapping) libraries

    • ORM frameworks map table to a class
    • we can write the code where we deal with objects (records)
    • The advantage of using orm framework is your code works with any relational database.
    • Examples
      • Java: Hibernate
      • .net: EntityFramework
      • python: SQL Alchemy

    ---

    Application Types

    • Commandline
    • Desktop/Mobile Apps
    • Web:
      • Web Apps
      • Web APIs

    WebSite (WebApps)

    • Generation 1: Readonly
      • Technologies:
        • html, css, javascript
        • server: apache, iis
    • Generation 2: Interactivity
      • Technologies:
        • PHP, ASP, Servlets
        • Databases:
    • Generation 3: Improvements
      • Technologies
        • Asp.net, JSP, Python Django …, bootstrap (css)
        • Databases
    • Generation 4: Mobile Apps , Desktop Apps with Web
      

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