数据库的创建，数据库的操作（增删改查）

最新推荐文章于 2021-02-22 17:40:36 发布

LI0_0BIN

最新推荐文章于 2021-02-22 17:40:36 发布

阅读量562

点赞数

CC 4.0 BY-SA版权

文章标签：数据库

本文链接：https://blog.youkuaiyun.com/LI0_0BIN/article/details/51908454

本文介绍了一个使用Java实现的SQLite数据库操作示例，包括数据库的创建、表的创建、数据的增删查改等基本操作。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >


public class MySQLiteOpenHelper extends SQLiteOpenHelper {
//创建数据库
    public MySQLiteOpenHelper(Context context) {
        super(context, "MyDatabase.db", null, 1);
        // TODO Auto-generated constructor stub
    }
//创建表
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table product_collect (c_id integer primary key autoincrement,id varchar,name varchar,pic varchar,price varchar,marketprice varchar,comment_count varchar)");
        db.execSQL("create table product_mycart (mc_id integer primary key autoincrement,id varchar,name varchar,pic varchar,price varchar,number varchar)");

    }
//数据库版本更新
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         db.execSQL("drop if table exists product_collect");
         db.execSQL("drop if table exists  product_mycart");
         onCreate(db);
    }

ublic class CollectDao {
    private MySQLiteOpenHelper sqLiteOpenHelper;

    public CollectDao(Context context) {
        sqLiteOpenHelper = new MySQLiteOpenHelper(context);
    }
    /**
     * 添加数据
     */

    public void addCart(Product product)
    {
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();

        ContentValues values=new ContentValues();
        values.put("id", product.id);
        values.put("name", product.name);
        values.put("pic", product.pic);
        values.put("price", product.price);
        values.put("number", product.number);


        database.insert("product_mycart", null, values);
        database.close();
    }

    /**
     * 删除数据
     */

    public void delCart(String name)
    {
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();

        database.delete("product_mycart", "name=?", new String[]{name});
        database.close();
    }

    /**
     * 查询数据，返回集合
     */

    public ArrayList<ProductAddCart> queryCart()
    {
        ArrayList<ProductAddCart> cartList=new ArrayList<ProductAddCart>();
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();
        Cursor cursor = database.query("product_mycart", null, null, null, null, null, null, null);

        while(cursor.moveToNext())
        {
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String pic = cursor.getString(cursor.getColumnIndex("pic"));
            String price = cursor.getString(cursor.getColumnIndex("price"));
            String number = cursor.getString(cursor.getColumnIndex("number"));
            int money=Integer.parseInt(price)*Integer.parseInt(number);

            cartList.add(new ProductAddCart(name,pic,money+"",number));
        }


        database.close();
        return cartList;
    }

    /**
     * 查询数据是否在数据库中
     */

    public boolean queryCart(String name)
    {
        boolean f=false;
        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();
        Cursor cursor = database.query("product_mycart", null, "name = ?", new String[]{name}, null, null, null, null);

        while(cursor.moveToNext())
        {
            f=true;

        }
        database.close();
        return f;
    }



}