import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;

public class DBHelper extends SQLiteOpenHelper {

 private final static String DB_NAME ="test.db";//數據庫名
 private final static int VERSION = 1;//版本號

 //自帶的構造方法
 public DBHelper(Context context, String name, CursorFactory factory,
   int version) {
  super(context, name, factory, version);
 }

 //為了每次構造時不用傳入dbName和版本號，自己得新定義一個構造方法
 public DBHelper(Context cxt){
  this(cxt, DB_NAME, null, VERSION);//調用上面的構造方法
 }

 //版本變更時
 public DBHelper(Context cxt,int version) {
  this(cxt,DB_NAME,null,version);
 }

 //當數據庫創建的時候調用
 public void onCreate(SQLiteDatabase db) {
  String sql = "create table student(" +
      "id integer primary key autoincrement," +
      "name varchar(20)," +
      "age int)";

  db.execSQL(sql);
 }

 //版本更新時調用
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  String sql  = "update student ....";//自己的Update操作
  db.execSQL(sql);
 }

}

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import cn.learn.db.dao.domain.Student;
import cn.learn.db.util.DBHelper;

public class StudentDao {

 DBHelper helper = null;

 public StudentDao(Context cxt) {
  helper = new DBHelper(cxt);
 }

 /**
  * 當Activity中調用此構造方法，傳入一個版本號時，系統會在下一次調用數據庫時調用Helper中的onUpgrade()方法進行更新
  * @param cxt
  * @param version
  */
 public StudentDao(Context cxt, int version) {
  helper = new DBHelper(cxt, version);
 }

 // 插入操作
 public void insertData(Student stu) {
  String sql = "insert into student (name,age)values(?,?)";
  SQLiteDatabase db = helper.getWritableDatabase();
  db.execSQL(sql, new Object[] { stu.name, stu.age });
 }

 // 其它操作

}