Database Servers and Clients
1. Big Picture (beginner — restaurant!)
Server = kitchen holding data (MySQL, Oracle, PostgreSQL — always ON!). Client = waiter asking (your Java program via JDBC!). Talk via SQL (order language!) over network!
2. Roles Table (exam!)
| Side | Job | Example |
|---|---|---|
| Server | stores tables, runs SQL, guards (users/rights!) | MySQL on port 3306, college DB |
| Client | connects, sends SQL, shows results | Java + JDBC, browser, CLI mysql |
| SQL | common order language | SELECT * FROM student WHERE id=1 |
| Network | road between! | localhost:3306/college (URL!) |
3. Tiny Flow (memorize!)
Java (client!) --JDBC+SQL--> MySQL (server!) --rows--> Java prints!
Server steps: parse SQL → plan → read tables/indexes → send rows. Many clients share ONE server (locking/transactions keep sane!).
4. Local Setup (beginner lab!)
Install MySQL/XAMPP → start server → create DB: CREATE DATABASE college; → create user/pass → Java connects (next topics!). Test: mysql -u root -p connects?
5. Exam Points
- Server vs client + SQL role — 5 marks, frequent.
- Port/URL idea + local setup steps — 3 marks, frequent.