SQLiteOpenHelper

public class DatabaseHelper extends SQLiteOpenHelper 
{
 //类没有实例化,是不能用作父类构造器的参数,必须声明为静态
 private static final String name = "future"; //数据库名称
 private static final int version = 1; //数据库版本 public DatabaseHelper(Context context) 
{
 super(context, name, null, version);
 } @Override 
public void onCreate(SQLiteDatabase db) 
{
 db.execSQL("CREATE TABLE IF NOT EXISTS user (personid integer primary key
 autoincrement, name varchar(20), age INTEGER)");
 }
 @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
 {
 db.execSQL(" ALTER TABLE user ADD phone VARCHAR(12) NULL "); //往表中增加一列
 // DROP TABLE IF EXISTS person 删除表
 }
 }