Interfész használata

• Szerző: Sallai András
• Copyright © 2020, Sallai András
• Licenc: CC BY-SA 4.0
• Web: https://szit.hu

A Python nyelv nem támogatja az interfész használatát, de használhatunk egy interface modult.

Employee.py

class Employee:
    def __init__(self, id, name, city, salary):
        self.id = id
        self.name = name
        self.city = city
        self.salary = salary

iDatabase.py

from interface import Interface
 
class iDatabase(Interface):
 
    def connectDb(self):
        pass

Mariadb.py

from interface import implements
from iDatabase import iDatabase
from mariadb import connect, Error
import sys
 
class Mariadb(implements(iDatabase)):
    def tryConnectDb(self):
        print('Működik')
        config = {
            'host': 'localhost',
            'user': 'feherbt',
            'password': 'titok'
        }
        conn = connect(**config, database='feherbt')
        return conn
 
    def connectDb(self):
        try:
            conn = self.tryConnectDb()
        except Error as err:
            print('Hiba! A kapcsolódás sikertelen!')
            print(err, file=sys.stderr)
        return conn
 
 
if __name__ == '__main__':
    Mariadb().connectDb()

A „database: iDatabase” állítás jelzi, hogy iDatabase paramétert várunk, de maga a Python nyelv nem követeli meg, hogy ténylegesen azt adjuk át paraméterként a hívás helyén.

DataManager.py

from iDatabase import iDatabase
from Mariadb import Mariadb
from Employee import Employee
 
class DataManager:
    def __init__(self,  database: iDatabase):
        self.database = database
 
    def getEmployees(self):
        conn = self.database.connectDb()
        cur = conn.cursor()
        sql = 'select * from employees'
        cur.execute(sql)
 
        employeeList = []
        for (id, name, city, salary) in cur:
            employee = Employee(id, name, city, salary)
            employeeList.append(employee)
        return employeeList
 
    def insertEmployee(self, employee: Employee):
        conn = self.database.connectDb()
        cur = conn.cursor()
        sql = """
                insert into employees
                (name, city, salary) values
                (?, ?, ?)
              """ 
        values = (employee.name, employee.city, employee.salary)
        cur.execute(sql, values)
        conn.commit()
        conn.close()
 
if __name__ == '__main__':
    data_manager = DataManager(Mariadb())

program01.py

from DataManager import DataManager
from Mariadb import Mariadb
from Employee import Employee
 
data_manager = DataManager(Mariadb())
 
employee = Employee(0, 'Reke Imre', 'Szeged', 4740000)
data_manager.insertEmployee(employee)
 
employees = data_manager.getEmployees()
 
for employee in employees:
    print(employee.name)