Source Of Summary:

Handout 4 - DBMS.pdf

1. Understanding Databases: SQL vs NoSQL 🤔💾

• The lecture discuss two main types of database systems: SQL (Relational) and NoSQL (Non-relational).
• While SQL databases have been a common choice since the 1980s and have replaced older types like hierarchical and network databases, they are now often used alongside NoSQL databases.
• The choice between them depends on the data you have and your specific needs. 🔄🎯

2. SQL Databases (RDBMS) ✅📊

2.1. What they are:

• SQL databases are typically implemented using a Relational Database Management System (RDBMS).
• RDBMS is the foundation for many modern database systems, including MySQL, Microsoft SQL Server, Oracle, and Microsoft Access.

2.2. How they work:

• RDBMS programs maintain a relational database and use SQL queries to access the data. 🔍💻

2.3. Relational Model:

• Invented by E. F. Codd in 1970. In the relational model, data is presented as tables of tuples.
• In SQL specifically, tables are viewed as lists of rows, and duplicates are allowed.
• Key Features:
  • They basically enforce ACID properties on database servers.
  • ACID stands for:
    • Atomicity: Implied by main features. 💥
    • Consistency: Once data is written, all future read requests will contain that data. 🔄
    • Isolation: Implied by main features. 🔒
    • Durability: Implied by main features. 💪
  • They use typed columns. 📏
  • They often involve normalized data. 🔄
  • They support complex queries. 🧠
  • They have their own query optimizer. ⚡
  • They provide a consistent way of accessing data using SQL. 🔍

2.4. SQL (Structured Query Language):