HSQLDB

HSQLDB is a 100% Java database which is embeddable. It has a small footprint and can be used for self-contained applications. The source files, the JAR file and support documents can be downloaded from hsqldb.org. It also provides a JDBC driver. HSQLDB is perfect for quick implementation and testing.

Following is a sample program which uses the JDBC driver for creating a table, inserting some data in the table and listing the rows from the table:

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.SQLException;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.PreparedStatement;

public class HSQLTest {
 Connection conn;
 Statement stmt;
 PreparedStatement add_stmt, get_stmt;
 
 static {
  try{
   Class.forName("org.hsqldb.jdbcDriver").newInstance();
  }
  catch(ClassNotFoundException e) {
   e.printStackTrace();
  }
  catch(InstantiationException e) {
   e.printStackTrace();
  }
  catch(IllegalAccessException e) {
   e.printStackTrace();
  }
 }
 
 HSQLTest() {
  try {
   initializeDB();
   createTable();
   populateTable();
   displayRows();
  }
  catch(SQLException e) {
   e.printStackTrace();
  }
 }
 
 void initializeDB() throws SQLException {
  conn = DriverManager.getConnection("jdbc:hsqldb:db/test", "sa", "");
  stmt = conn.createStatement();
 }
 
 public void createTable() throws SQLException {
  String table_name = "sample_table";
  DatabaseMetaData dbM = conn.getMetaData();
  ResultSet rs = dbM.getTables(null, null, "%", null);
  boolean found = false;
  while(rs.next()) {
   String s = rs.getString(3);
   //System.out.println(s);
   if(s.equalsIgnoreCase(table_name)) {
    found = true;
    break;
   }
  }
  
  if(!found) {
   String s = "CREATE TABLE " + table_name + "(id INTEGER GENERATED BY DEFAULT AS IDENTITY(START WITH 1000) PRIMARY KEY, " +
      "category VARCHAR(40), name VARCHAR(40))";
   stmt.execute("SET WRITE_DELAY FALSE;");
   stmt.executeUpdate(s);
  }
 }
 
 public void populateTable() throws SQLException {
  stmt.executeUpdate("insert into SAMPLE_TABLE (category, name) values ('E0', 'Ben')");
 }
 
 public void displayRows() throws SQLException {
  ResultSet rs = stmt.executeQuery("SELECT * FROM SAMPLE_TABLE");
  int numCols = rs.getMetaData().getColumnCount();
  while(rs.next()) {
   for(int i=1; i<=numCols; i++) {
    System.out.println(rs.getString(i) + ": " + rs.getString(i));
   }
  }
 }
 
 public static void main(String[] args) {
  HSQLTest hTest = new HSQLTest();
 }
}