SQLiteOpenHelper的原生数据库

最新推荐文章于 2020-09-28 15:38:48 发布

原创最新推荐文章于 2020-09-28 15:38:48 发布 · 190 阅读

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本文介绍了一个用于Android平台的SQLite数据库帮助类实现，包括数据库的创建、表结构定义及增删改查等基本操作。通过具体代码示例展示了如何进行数据的插入、查询、更新和删除。

创建库的帮助类

public class MySqlit extends SQLiteOpenHelper {
    public MySqlit(Context context) {
        super(context,"User.db",null,1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table user(aid text,title text,description text)");
    }

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

    }
}

UserDao的增删改查

public class Userdao {
   private Sqlist sqlist;
   public Userdao(Context context) {
       sqlist = new Sqlist(context);
   }
   public void add(String name,String price,String brand){
       SQLiteDatabase database = sqlist.getReadableDatabase();
       database.execSQL("insert into user(id,name,price,brand) values(null,?,?,?)",
               new String[]{name,price,brand});
       database.close();
   }
   public List<User> select(){
       List<User> list = new ArrayList<User>();
       SQLiteDatabase database = sqlist.getReadableDatabase();
       Cursor cursor = database.rawQuery("select * from user",
               new String[]{});
       while(cursor.moveToNext()){
           int id = cursor.getInt(cursor.getColumnIndex("id"));
           String name = cursor.getString(cursor.getColumnIndex("name"));
           String price = cursor.getString(cursor.getColumnIndex("price"));
           String brand = cursor.getString(cursor.getColumnIndex("brand"));
           User user = new User(name, price, brand);
           list.add(user);
       }
       return list;
   }
   public void delete(String name){
       SQLiteDatabase database = sqlist.getReadableDatabase();
       database.execSQL("delete from user where name=?", new String[]{name});
       database.close();
   }
   public void update(String tj,String newname,String newprice,String newbrand){
       SQLiteDatabase database = sqlist.getReadableDatabase();
       database.execSQL("update user set name=?,price=?,brand=? where name=?",
               new String[]{newname,newprice,newbrand,tj});
       database.close();
   }
}