테이블 생성 코드 data = [[1, 1], [1, 2], [1, 3], [2, 1], [2, 4]] project = pd.DataFrame(data, columns=['project_id', 'employee_id']).astype({'project_id':'Int64', 'employee_id':'Int64'}) data = [[1, 'Khaled', 3], [2, 'Ali', 2], [3, 'John', 1], [4, 'Doe', 2]] employee = pd.DataFrame(data, columns=['employee_id', 'name', 'experience_years']).astype({'employee_id':'Int64', 'name':'object', 'experience_yea..