PostgreSQL Java Tutorial: Creating Tables

Summary: in this tutorial, you will learn how to create tables in a PostgreSQL database from a Java program using JDBC.

Table of Contents

Creating table program

The following example shows how to create tables in the PostgreSQL database from a Java program:

import java.sql.SQLException;

public class Main {
    public static void main(String[] args) {

        var sql = "CREATE TABLE products (" +
                "    id SERIAL PRIMARY KEY," +
                "    name VARCHAR(255) NOT NULL," +
                "    price DECIMAL(10, 2) NOT NULL" +
                ");";
        try (var conn =  DB.connect();
             var stmt = conn.createStatement()) {
            stmt.executeUpdate(sql);
        } catch (SQLException e) {
            System.err.println(e.getMessage());
        }
    }
}

How it works.

First, construct a CREATE TABLE statement that creates the products table:

var sql = "CREATE TABLE products (" +
            "    id SERIAL PRIMARY KEY," +
            "    name VARCHAR(255) NOT NULL," +
            "    price DECIMAL(10, 2) NOT NULL" +
            ");";

Second, establish a connection to sales database on the local PostgreSQL server using the DB class:

var conn =  DB.connect();

Third, create a Statement by calling the createStatement() method of the Connection object:

var stmt = conn.createStatement()

Fourth, execute the CREATE TABLE statement by calling the executeUpdate() method.

stmt.executeUpdate(sql);

The try-catch statement will display an error message if any SQLException occurs.

Since the connect() and createStatement() method calls are wrapped in a try-with-resources statement, the Statement and Connection will be closed properly.

If you run the program, it’ll create the products in the sales database.

Verify the table creation

First, open the Command Prompt on Windows or Terminal on Unix-like systems.

Second, connect to the sales database on the local PostgreSQL server using the psql client tool:

psql -U postgres -d sales

It’ll prompt you for a password.

Third, use the \dt command to show tables in the sales database:

\dt

Output:

          List of relations
 Schema |   Name   | Type  |  Owner
--------+----------+-------+----------
 public | products | table | postgres
(1 row)

The output indicates that the products table has been created successfully.

Summary

Call the executeUpdate() method of a Statement object to execute a CREATE TABLE statement to create a new table in the PostgreSQL database.