Introduction to Relational database management system

Introduction to Relational database management system

1. Data vs Database

2. DBMS If the database is the Room, the DBMS is your PA who: Puts laundry in the right place (wash) Brings them to you when you ask (retrieve) Keeps things neat and maintains (integrity) Locks the room so only authorized people can open it (security).

3. Applications of DBMS Tell the story of "Ravi’s Day": Morning: withdraws money (Bank DBMS) Goes to college (Education DBMS) Visits hospital with friend (Healthcare DBMS) Orders online (E-commerce DBMS) Shares a photo on Instagram (Social Media DBMS) Books a train ticket (Transportation DBMS) → Show how DBMS silently runs everywhere in daily life.

4. Types of Database Users Naïve user → customer reading menu Application programmer → chef following recipes (writes code) Sophisticated user → food critic directly asking for ingredients list (writes queries) Specialized user → celebrity chef creating fusion dishes (AI or simulation systems) DBA → restaurant manager ensuring smooth operations.

5. Keys in DBMS Primary Key → Your Aadhaar number (unique & mandatory) Candidate Keys → Passport, Driving License (possible uniques ) Super Key → Aadhaar + Name (still unique, but extra info) Alternate Key → Passport (unused candidate) Foreign Key → College ID in library system (links to main student table)

6. Composite Key → {Bus number + Date} to identify a trip Unique Key → Phone number (unique but can be NULL) Surrogate Key → Auto-generated roll number in database.