def find_by_id(self, id):
"""
Validate ID type is int
Returns Author if exists
:param id: int
:return: Author | None
"""
# Validate type
if not TypeUtils.is_type(id, var_type=int):
print(ErrorMsgUtils.type_error(id, var_type=int))
return
sql = f"SELECT * FROM AUTHOR WHERE ID = {id}"
# Execution
try:
self.cursor.execute(sql)
results = self.cursor.fetchone()
if not results:
print(
ErrorMsgUtils.does_not_exists(table_name='Author', var=id))
return
# Return results
return Author(id=results[0],
first_name=results[1],
last_name=results[2])
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
def find_by_id(self, id):
"""
Validates ID type is int
Returns Book by ID if exists
:param id: int
:return: Book | None
"""
# Validates type
if not TypeUtils.is_type(id, var_type=int):
print(ErrorMsgUtils.type_error(id, var_type=int))
return
# Execution
sql = f"SELECT * FROM BOOKS WHERE ID = {id}"
try:
self.cursor.execute(sql)
results = self.cursor.fetchone()
if not results:
print(ErrorMsgUtils.does_not_exists(table_name='Book', var=id))
return None
# Return results
book_by_id = Book(
id=results[0],
name=results[1],
price=results[2],
author_id=results[3],
)
return book_by_id
# Error
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
def find_by_name(self, name):
"""
Validates Name type is str
:param name: str
:return: Book | None
"""
# Validates type
if not TypeUtils.is_type(name, var_type=str):
print(ErrorMsgUtils.type_error(name, var_type=str))
return
# Execution
sql = f"SELECT * FROM BOOKS WHERE NAME = '{name}'"
try:
self.cursor.execute(sql)
results = self.cursor.fetchone()
if not results:
print(
ErrorMsgUtils.does_not_exists(table_name='Book', var=name))
return None
# Returns results
book_by_name = Book(id=results[0],
name=results[1],
price=results[2],
author_id=results[3])
return book_by_name
# Error
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
def create_book(self, name, price, author):
"""
Validates name & price & author type
Validates Book is not exists by name
Creates a new book into the BOOKS's table
:param name: str
:param price: int | float
:param author: Author
:return: Book | None
"""
# Validates name
if not TypeUtils.is_type(name, var_type=str):
print(ErrorMsgUtils.type_error(name, var_type=str))
return
# Validates price
if not TypeUtils.is_type_or(price, var_type1=int, var_type2=float):
print(ErrorMsgUtils.none_of_type(int, float, var=print()))
return
# Validates author
if not TypeUtils.is_type(author, var_type=Author):
print(ErrorMsgUtils.type_error(author, var_type=Author))
return
# Validates existence
book_to_check = self.find_by_name(name)
if book_to_check is not None:
print(ErrorMsgUtils.already_exists(name))
return
# Validates author existence
author_db = AuthorDBDAO(db=self.db)
author_by_id = author_db.find_by_id(author.id)
if author_by_id is None:
print(
ErrorMsgUtils.does_not_exists(table_name='Author',
var=author.id))
return
# SQL & Execution
sql = f"INSERT INTO BOOKS (NAME, PRICE, AUTHOR_ID) VALUES ('{name}', {price}, {author.id})"
try:
self.cursor.execute(sql)
self.db.commit()
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
# Return None
return None
else:
print(self.cursor.rowcount, "was inserted.")
print("ID: ", self.cursor.lastrowid)
# Return the Book
return Book(name=name,
price=price,
id=self.cursor.lastrowid,
author_id=author.id)
def find_by_name(self, first_name, last_name):
"""
Validates first_name & last_name are str
Returns Author if exists
:param first_name: str
:param last_name: str
:return: Author | None
"""
# Validates type
if not TypeUtils.all_of_type(first_name, last_name, var_type=str):
print(ErrorMsgUtils.type_error(first_name, last_name,
var_type=str))
return
# Validate legal value
if not first_name:
print(ErrorMsgUtils.illegal_value(first_name))
if not last_name:
print(ErrorMsgUtils.illegal_value(last_name))
sql = f"SELECT * FROM AUTHOR WHERE FIRST_NAME = '{first_name}' AND LAST_NAME = '{last_name}'"
# Execution
try:
self.cursor.execute(sql)
results = self.cursor.fetchone()
if not results:
print(
ErrorMsgUtils.does_not_exists(
table_name='Author', var=f"{first_name}, {last_name}"))
return
# Return results
return Author(id=results[0],
first_name=results[1],
last_name=results[2])
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
def update_book(self, book):
"""
Validates Book type is Book
:param book: Book
:return: Updated Book | None
"""
# Validates type
if not TypeUtils.is_type(book, var_type=Book):
print(ErrorMsgUtils.type_error(book, var_type=Book))
return
# Validate existence
book_to_update = self.find_by_id(book.id)
if book_to_update is None:
print(ErrorMsgUtils.does_not_exists(table_name='Book',
var=book.id))
return
# Execution
sql = f"UPDATE BOOKS SET NAME = '{book.name}', " \
f"PRICE = '{book.price}' " \
f"WHERE ID = {book.id}"
try:
self.cursor.execute(sql)
self.db.commit()
# Error
except mysql.connector.Error as error:
print(ErrorMsgUtils.display_error(error))
return None
else:
# Return updated Book
print(self.cursor.rowcount, "was updated.")
updated_book = self.find_by_id(book.id)
return updated_book