JDBC Fundamentals

JDBC (Java Database Connectivity) is the standard API for talking to relational databases from Java.

• It lives in the java.sql package.
• Each database ships a driver that implements the JDBC interfaces.
• You write code against interfaces like Connection, Statement, and ResultSet — never against the vendor classes directly.

This abstraction lets the same code work against PostgreSQL, MySQL, H2, or Oracle.

Three interfaces do most of the work:

• Connection — an open session with the database.
• Statement / PreparedStatement — sends SQL.
• ResultSet — a cursor over the rows returned by a query.

You obtain a Connection from DriverManager or a DataSource.