Question

我想在python环境中创建一个mysql数据库，然后在其中创建表，但是错误显示“未选择数据库”。我该如何解决？

import mysql.connector
dbname = input('Please enter the name of database : ')
db = mysql.connector.connect(
host = '127.0.0.1',
user = 'root',
password = ''
)


cursor = db.cursor()
cursor.execute("CREATE DATABASE IF NOT EXISTS %s" %dbname)
cursor.execute("CREATE TABLE IF NOT EXISTS %s (email varchar(30) pwd varchar(20))" %dbname)

db.close()

Answer 1

在您的代码中，创建数据库连接器后无法识别数据库名称，因为未为连接器提供数据库名称。这意味着在数据库中创建表时，必须向连接器提供数据库名称，然后才能在指定的数据库中创建表通过连接器。

首先，您需要按照以下步骤创建数据库。

public class FarsiBadr extends Fragment {
    RecyclerViewAdapter myAdapter;
    List<Items> lstItems;
    public FarsiBadr() {
        // Required empty public constructor
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_farsi_badr, container, false);
        lstItems = new ArrayList<>();
        lstItems.add(new Items("1 Tv", "11111", "77777", "horizental", R.drawable.gemtv));
        lstItems.add(new Items("2 Tv", "22222", "88888", "horizental", R.drawable.bbc));
        lstItems.add(new Items("3 Tv", "33333", "99999", "horizental", R.drawable.voa));
        lstItems.add(new Items("4 Tv", "44444", "44444", "horizental", R.drawable.manoto));
        //horizontal recycler view
        RecyclerView myrv = view.findViewById(R.id.recyclerview_id_Horizental_badr_farsi);
        myAdapter = new RecyclerViewAdapter(getContext(), lstItems);
        myrv.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false));
        myrv.setAdapter(myAdapter);
        //vertical mode
        RecyclerView verticalmode = view.findViewById(R.id.recyclerview_id_vertical_badr_farsi);
        myAdapter = new RecyclerViewAdapter(getContext(), lstItems);
        verticalmode.setLayoutManager(new GridLayoutManager(getContext(), 3));
        verticalmode.setAdapter(myAdapter);
        return view;
    }

}

创建数据库后，您需要手动提供数据库名称才能在现有数据库中创建数据库表。这里dbname由用户即输入

       import mysql.connector
       dbname = input('Please enter the name of database : ')
       db = mysql.connector.connect(
       host = 'localhost',
       user = 'root',
       password = '',
       )

      cursor = db.cursor()
      cursor.execute("CREATE DATABASE IF NOT EXISTS %s" %dbname)
      cursor.close()
      db.close()}

最后，您可以要求用户输入数据库名称，并可以使用以下代码在数据库中以相同的名称（在您的情况下为dbname）创建表。

      import mysql.connector
      db = mysql.connector.connect(
      host = 'localhost',
      user = 'root',
      password = '',
      database=dbname, #providing name of database to connector
      )

      cursor = db.cursor()
      cursor.execute("CREATE TABLE IF NOT EXISTS %s (email VARCHAR(30),pwd 
      VARCHAR(20))" %dbname)
      cursor.close()
      db.close()}

如何从用户输入获取mysql数据库名称的名称并创建表

1 个答案: