JDBC

• Java Database Connectivity

Basic Process

1. get JAR file for each DB
2. Prepare username, password, jdbcurl for db
3. Create Connection
4. Create PreparedStatement
5. Get Result from 4.
6. Work with Result
7. Close Result
8. Close PreparedStatement
9. Close Connection

Sample

javaCopy
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class Jdbc {

  private static Connection conn;

  {
    try {
      Class.forName("org.h2.Driver");
      getConnection();
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
  }

  public static Connection getConnection() {
  try {
    conn = DriverManager.getConnection("jdbc:h2:~/test", "sa", "");
    return conn;
  } catch (SQLException e) {
    e.printStackTrace();
  }
  return null;
  }

  public static void addUser(long id, String name) {
    String sql = "INSERT INTO USER (ID, NAME) VALUES (?, ?)";
    PreparedStatement pstmt;
    try {
      pstmt = conn.prepareStatement(sql);
      pstmt.setLong(1, 1);
      pstmt.setString(2, "kenu");
      pstmt.executeUpdate();
      pstmt.close();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

DB Info

textCopy
spring.datasource.username=devuser
spring.datasource.password=devpass

spring.datasource.url=jdbc:postgresql://localhost:5432/devdb
spring.datasource.platform=postgres

spring.datasource.url=jdbc:mariadb://localhost:3306/devdb
spring.datasource.platform=mariadb

spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/devdb
spring.datasource.platform=mysql

spring.datasource.url=jdbc:oracle:thin:@localhost:1521:devdb
spring.datasource.platform=oracle

# spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# spring.datasource.driver-class-name=org.postgresql.Driver
# spring.datasource.driver-class-name=org.mariadb.jdbc.Driver
# spring.datasource.driver-class-name=oracle.jdbc.OracleDriver

spring.datasource.hikari.maximum-pool-size=4

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql: true