React native 反应原生的SQLite

我试图在我的react原生应用程序中实现sqlite，但回调函数没有产生任何结果

 register = () => {
        const username= this.state.username;
        const userContact = this.state.user_contact;
        const userAddress = this.state.user_address;

        console.log(username, userContact, userAddress);

        if (!username) {
          alert('Please fill name');
          return;
        }
        if (!userContact) {
          alert('Please fill Contact Number');
          return;
        }
        if (!userAddress) {
          alert('Please fill Address');
          return;
        }
    
        db.transaction(function (tx) {
          tx.executeSql(
            'INSERT INTO user_table (username, user_contact, user_address) VALUES (?,?,?)',
            [username, userContact, userAddress],
            (tx, results) => {
              console.log('Results', results.rowsAffected);
              if (results.rowsAffected > 0) {
                Alert.alert(
                  'Success',
                  'You are Registered Successfully',
                  [
                    {
                      text: 'Ok',
                      onPress: () => this.props.navigation.navigate('HomeScreen'),
                    },
                  ],
                  { cancelable: false }
                );
              } else alert('Registration Failed');
            }
          );
        });
}

它不会生成显示用户已注册的警报，也不会出现错误

希望有人能帮忙。谢谢：）