Java Tutorial/Database/Insert Update Delete

Delete All Rows from a Database Table Using a Statement?

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class Main {
  public static void main(String[] args) throws Exception {
    Connection conn = getConnection();
    Statement stmt = conn.createStatement();

    stmt.executeUpdate("create table survey (id int, name CHAR(5) );");
    stmt.executeUpdate("INSERT INTO survey(id, name)VALUES(111, "123456789")");
    ResultSet rs = stmt.executeQuery("SELECT * FROM survey");
    outputResultSet(rs);
    stmt.executeUpdate("delete from survey");
    
    rs = stmt.executeQuery("SELECT * FROM survey");
    outputResultSet(rs);
    
    
    rs.close();
    stmt.close();
    conn.close();
  }
  private static void outputResultSet(ResultSet rs) throws Exception {
    ResultSetMetaData rsMetaData = rs.getMetaData();
    int numberOfColumns = rsMetaData.getColumnCount();
    for (int i = 1; i < numberOfColumns + 1; i++) {
      String columnName = rsMetaData.getColumnName(i);
      System.out.print(columnName + "   ");
    }
    System.out.println();
    System.out.println("----------------------");
    while (rs.next()) {
      for (int i = 1; i < numberOfColumns + 1; i++) {
        System.out.print(rs.getString(i) + "   ");
      }
      System.out.println();
    }
  }
  private static Connection getConnection() throws Exception {
    Class.forName("org.hsqldb.jdbcDriver");
    String url = "jdbc:hsqldb:mem:data/tutorial";
    return DriverManager.getConnection(url, "sa", "");
  }
}

ID   NAME   
----------------------
111   123456789   
ID   NAME   
----------------------

Insert a Row into a Database Table Using a Statement

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class Main {
  public static void main(String[] args) throws Exception {
    Connection conn = getConnection();
    Statement stmt = conn.createStatement();

    stmt.executeUpdate("create table survey (id int, name CHAR(5) );");
    stmt.executeUpdate("INSERT INTO survey(id, name)VALUES(111, "123456789")");
    ResultSet rs = stmt.executeQuery("SELECT * FROM survey");
    outputResultSet(rs);
    stmt.executeUpdate("drop table survey");
    
    rs.close();
    stmt.close();
    conn.close();
  }
  private static void outputResultSet(ResultSet rs) throws Exception {
    ResultSetMetaData rsMetaData = rs.getMetaData();
    int numberOfColumns = rsMetaData.getColumnCount();
    for (int i = 1; i < numberOfColumns + 1; i++) {
      String columnName = rsMetaData.getColumnName(i);
      System.out.print(columnName + "   ");
    }
    System.out.println();
    System.out.println("----------------------");
    while (rs.next()) {
      for (int i = 1; i < numberOfColumns + 1; i++) {
        System.out.print(rs.getString(i) + "   ");
      }
      System.out.println();
    }
  }
  private static Connection getConnection() throws Exception {
    Class.forName("org.hsqldb.jdbcDriver");
    String url = "jdbc:hsqldb:mem:data/tutorial";
    return DriverManager.getConnection(url, "sa", "");
  }
}

ID   NAME   
----------------------
111   123456789

Update a Row in a Database Table Using a Statement

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class Main {
  public static void main(String[] args) throws Exception {
    Connection conn = getConnection();
    Statement stmt = conn.createStatement();

    stmt.executeUpdate("create table survey (id int, name CHAR(5) );");
    stmt.executeUpdate("INSERT INTO survey(id, name)VALUES(111, "123456789")");
    ResultSet rs = stmt.executeQuery("SELECT * FROM survey");
    outputResultSet(rs);
    stmt.executeUpdate("update survey set name="newName" where id = 111");
    
    rs = stmt.executeQuery("SELECT * FROM survey");
    outputResultSet(rs);
    
    
    rs.close();
    stmt.close();
    conn.close();
  }
  private static void outputResultSet(ResultSet rs) throws Exception {
    ResultSetMetaData rsMetaData = rs.getMetaData();
    int numberOfColumns = rsMetaData.getColumnCount();
    for (int i = 1; i < numberOfColumns + 1; i++) {
      String columnName = rsMetaData.getColumnName(i);
      System.out.print(columnName + "   ");
    }
    System.out.println();
    System.out.println("----------------------");
    while (rs.next()) {
      for (int i = 1; i < numberOfColumns + 1; i++) {
        System.out.print(rs.getString(i) + "   ");
      }
      System.out.println();
    }
  }
  private static Connection getConnection() throws Exception {
    Class.forName("org.hsqldb.jdbcDriver");
    String url = "jdbc:hsqldb:mem:data/tutorial";
    return DriverManager.getConnection(url, "sa", "");
  }
}

ID   NAME   
----------------------
111   123456789   
ID   NAME   
----------------------
111   newName