Android中数据库缓存

//写一个类继承SQLiteOpenHelper 

public class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
    super(context, name, factory, version);
}

@Override
public void onCreate(SQLiteDatabase db) {
    //创建数据库表
    db.execSQL("create table yk(id integer primary key autoincrement,data text)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

}

//写一个类实现增删改查
public class DbUtils {

private final SQLiteDatabase db;

public DbUtils(Context context){
    DbHelper dbHelper=new DbHelper(context,"exam.db",null,1);
    db = dbHelper.getWritableDatabase();
}

//插入数据
public void insert(String data){
    ContentValues values=new ContentValues();
    values.put("data",data);
    db.insert("yk",null,values);
    }  
}