Setting Up JDBC for PostgreSQL

Querying a PostgreSQL Database in Java

Miller Trujillo

Staff Software Engineer

Meet your instructor!

Miller Trujillo

Staff Engineer at Connectly.ai, ex-Microsoft, ex-Google
M.S. and B.S. in Computer Science

Polo & Miller

Why databases matter

Storing and retrieving data in different apps

$$ PostgreSQL database

Course overview

Chapter 1: Connecting Java to PostgreSQL
- JDBC, connection management, basic querying
Chapter 2: Advanced Query Techniques
- Prepared statements, filters, and joins
Chapter 3: Advanced Data Retrieval and Management
- Aggregations, transactions, large objects

Prerequisites

Data Types and Exceptions in Java Banner

Intermediate SQL Banner

JDBC

Java Database Connectivity
Standard API for database interaction
Database agnostic (PostgreSQL, MySQL, Oracle)

JDBS - visual

JDBC flow

Connecting to the database

String url = "jdbc:postgresql://localhost:5432/library";

String user = "postgres";

String password = "secret";


Connection conn = DriverManager.getConnection(url, user, password);

Host: server address
Port: database entry point

Try-with-resources

String url = "jdbc:postgresql://localhost:5432/library";
String user = "postgres";
String password = "secret";

Connection conn = DriverManager.getConnection(url, user, password);


try (Connection conn = DriverManager.getConnection(url, user, password)) {
  System.out.println("Connected to the database!");}

Opens a socket
Prevents memory leaks
Ensures the connection is closed

Let's practice!

Querying a PostgreSQL Database in Java