src/cpl_core/database/connection/database_connection.py

@@ -8,6 +8,7 @@ from cpl_core.database.connection.database_connection_abc import \
 from cpl_core.database.database_settings import DatabaseSettings
 from cpl_core.utils import CredentialManager
 from mysql.connector.abstracts import MySQLConnectionAbstract
+from mysql.connector.cursor import MySQLCursorBuffered
 
 
 class DatabaseConnection(DatabaseConnectionABC):
@@ -17,15 +18,30 @@ class DatabaseConnection(DatabaseConnectionABC):
     def __init__(self):
         DatabaseConnectionABC.__init__(self)
 
-        self._database_server: Optional[MySQLConnectionAbstract] = None
+        self._database: Optional[MySQLConnectionAbstract] = None
+        self._cursor: Optional[MySQLCursorBuffered] = None
         
     @property
     def server(self) -> MySQLConnectionAbstract:
-        return self._database_server
+        return self._database
+    
+    @property
+    def cursor(self) -> MySQLCursorBuffered:
+        return self._cursor
 
     def connect(self, database_settings: DatabaseSettings):
         try:
-            self._database_server = sql.connect(
+            connection = sql.connect(
+                host=database_settings.host,
+                user=database_settings.user,
+                passwd=CredentialManager.decrypt(database_settings.password),
+                charset=database_settings.charset,
+                use_unicode=database_settings.use_unicode,
+                buffered=database_settings.buffered,
+                auth_plugin=database_settings.auth_plugin
+            )
+            connection.cursor().execute(f'CREATE DATABASE IF NOT EXISTS `{database_settings.database}`;')
+            self._database = sql.connect(
                 host=database_settings.host,
                 user=database_settings.user,
                 passwd=CredentialManager.decrypt(database_settings.password),
@@ -35,6 +51,7 @@ class DatabaseConnection(DatabaseConnectionABC):
                 buffered=database_settings.buffered,
                 auth_plugin=database_settings.auth_plugin
             )
+            self._cursor = self._database.cursor()
             Console.set_foreground_color(ForegroundColorEnum.green)
             Console.write_line(f'[{__name__}] Connected to database')
             Console.set_foreground_color(ForegroundColorEnum.default)

src/cpl_core/database/connection/database_connection_abc.py

@@ -2,6 +2,7 @@ from abc import ABC, abstractmethod
 
 from cpl_core.database.database_settings import DatabaseSettings
 from mysql.connector.abstracts import MySQLConnectionAbstract
+from mysql.connector.cursor import MySQLCursorBuffered
 
 
 class DatabaseConnectionABC(ABC):
@@ -14,6 +15,10 @@ class DatabaseConnectionABC(ABC):
     @abstractmethod
     def server(self) -> MySQLConnectionAbstract: pass
     
+    @property
+    @abstractmethod
+    def cursor(self) -> MySQLCursorBuffered: pass
+    
     @abstractmethod
     def connect(self, database_settings: DatabaseSettings):
         r"""Connects to a database by connection string

src/cpl_core/database/context/database_context.py

@@ -8,6 +8,7 @@ from cpl_core.database.connection.database_connection_abc import \
 from cpl_core.database.context.database_context_abc import DatabaseContextABC
 from cpl_core.database.database_settings import DatabaseSettings
 from cpl_core.database.table_abc import TableABC
+from mysql.connector.cursor import MySQLCursorBuffered
 
 
 class DatabaseContext(DatabaseContextABC):
@@ -22,21 +23,22 @@ class DatabaseContext(DatabaseContextABC):
         DatabaseContextABC.__init__(self, database_settings)
 
         self._db: DatabaseConnectionABC = DatabaseConnection()
-        self._cursor: Optional[str] = None
         self._tables: list[TableABC] = TableABC.__subclasses__()
 
     @property
-    def cursor(self):
-        return self._cursor
+    def cursor(self) -> MySQLCursorBuffered:
+        return self._db.cursor
     
     def connect(self, database_settings: DatabaseSettings):
         self._db.connect(database_settings)
-        c = self._db.server.cursor()
-        self._cursor = c
         Console.write_line(f"Ts: {self._tables}")
         for table in self._tables:
-            Console.write_line(f"{table}, {table.create_string}")
-            c.execute(table.create_string)
+            Console.write_line(f"{table}, {table.get_create_string()}")
+            self._db.cursor.execute(table.get_create_string())
 
     def save_changes(self):
         self._db.server.commit()
+        
+    def select(self, statement: str) -> list:
+        self._db.cursor.execute(statement)
+        return self._db.cursor.fetchall()

src/cpl_core/database/context/database_context_abc.py

@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
 
 from cpl_core.database.database_settings import DatabaseSettings
+from mysql.connector.cursor import MySQLCursorBuffered
 
 
 class DatabaseContextABC(ABC):
@@ -11,8 +12,8 @@ class DatabaseContextABC(ABC):
         pass
 
     @property
-    @abstractmethod
-    def cursor(self): pass
+    def cursor(self) -> MySQLCursorBuffered:
+        return self._cursor
     
     @abstractmethod
     def connect(self, database_settings: DatabaseSettings):
@@ -24,6 +25,21 @@ class DatabaseContextABC(ABC):
         """
         pass
     
+    @abstractmethod
     def save_changes(self):
         r"""Saves changes of the database"""
         pass
+    
+    @abstractmethod
+    def select(self, statement: str) -> list:
+        r"""Runs SQL Statements
+        
+        Parameter
+        ---------
+            statement: :class:`str`
+        
+        Returns
+        -------
+            list: Fetched list of selected elements
+        """
+        pass

src/cpl_core/database/table_abc.py

@@ -18,9 +18,9 @@ class TableABC(ABC):
     def LastModifiedAt(self) -> datetime:
         return self._modified_at
     
-    @property
+    @staticmethod
     @abstractmethod
-    def create_string(self) -> str: pass
+    def get_create_string() -> str: pass
     
     @property
     @abstractmethod

src/tests/custom/database/src/application.py

@@ -26,10 +26,12 @@ class Application(ApplicationABC):
         self._logger.debug(__name__, f'Customer: {self._configuration.environment.customer}')
 
         user_repo: UserRepo = self._services.get_service(UserRepoABC)
+        if len(user_repo.get_users()) == 0:
             user_repo.add_test_user()
+        
         Console.write_line('Users:')
         for user in user_repo.get_users():
-            Console.write_line(user.UserId, user.Name, user.CityId, user.City.CityId, user.City.Name, user.City.ZIP)
+            Console.write_line(user.UserId, user.Name, user.City)
 
         Console.write_line('Cities:')
         for city in user_repo.get_cities():

src/tests/custom/database/src/model/city_model.py

@@ -3,44 +3,45 @@ from cpl_core.database import TableABC
 
 class CityModel(TableABC):
 
-    def __init__(self, name: str, zip_code: str):
-        self.CityId = 0
+    def __init__(self, name: str, zip_code: str, id = 0):
+        self.CityId = id
         self.Name = name
         self.ZIP = zip_code
     
-    @property
-    def create_string(self) -> str:
-        return f"""
+    @staticmethod
+    def get_create_string() -> str:
+        return str(f"""
             CREATE TABLE IF NOT EXISTS `City` (
                 `CityId` INT(30) NOT NULL AUTO_INCREMENT,
-                `Name` VARCHAR NOT NULL,
-                `ZIP` VARCHAR NOT NULL,
+                `Name` VARCHAR(64) NOT NULL,
+                `ZIP` VARCHAR(5) NOT NULL,
+                PRIMARY KEY(`CityId`)
             );
-        """
+        """)
     
     @property
     def insert_string(self) -> str:
-        return f"""
+        return str(f"""
             INSERT INTO `City` (
                 `Name`, `ZIP`
             ) VALUES (
                 '{self.Name}',
                 '{self.ZIP}'
             );
-        """
+        """)
     
     @property
     def udpate_string(self) -> str:
-        return f"""
+        return str(f"""
             UPDATE `City`
             SET `Name` = '{self.Name}', 
             `ZIP` = '{self.ZIP}',
             WHERE `CityId` = {self.Id};
-        """
+        """)
     
     @property
     def delete_string(self) -> str:
-        return f"""
+        return str(f"""
             DELETE FROM `City`
             WHERE `CityId` = {self.Id};
-        """
+        """)

src/tests/custom/database/src/model/user_model.py

@@ -5,46 +5,46 @@ from .city_model import CityModel
 
 class UserModel(TableABC):
 
-    def __init__(self, name: str, city: CityModel):
-        self.UserId = 0
+    def __init__(self, name: str, city: CityModel, id = 0):
+        self.UserId = id
         self.Name = name
-        self.CityId = city.CityId
+        self.CityId = city.CityId if city is not None else 0
         self.City = city
 
-    @property
-    def create_string(self) -> str:
-        return f"""
+    @staticmethod
+    def get_create_string() -> str:
+        return str(f"""
             CREATE TABLE IF NOT EXISTS `User` (
                 `UserId` INT(30) NOT NULL AUTO_INCREMENT,
-                `Name` VARCHAR NOT NULL,
-                `CityId` VARCHAR NOT NULL,
+                `Name` VARCHAR(64) NOT NULL,
+                `CityId` INT(30),
                 FOREIGN KEY (`UserId`) REFERENCES City(`CityId`),
                 PRIMARY KEY(`UserId`)
             );
-        """
+        """)
 
     @property
     def insert_string(self) -> str:
-        return f"""
+        return str(f"""
             INSERT INTO `User` (
                 `Name`
             ) VALUES (
                 '{self.Name}'
             );
-        """
+        """)
 
     @property
     def udpate_string(self) -> str:
-        return f"""
+        return str(f"""
             UPDATE `User`
             SET `Name` = '{self.Name}', 
             `CityId` = {self.CityId},
             WHERE `UserId` = {self.UserId};
-        """
+        """)
 
     @property
     def delete_string(self) -> str:
-        return f"""
+        return str(f"""
             DELETE FROM `User`
             WHERE `UserId` = {self.UserId};
-        """
+        """)

src/tests/custom/database/src/model/user_repo.py

@@ -1,4 +1,6 @@
+from cpl_core.console import Console
 from cpl_core.database.context import DatabaseContextABC
+
 from .city_model import CityModel
 from .user_model import UserModel
 from .user_repo_abc import UserRepoABC
@@ -9,21 +11,32 @@ class UserRepo(UserRepoABC):
     def __init__(self, db_context: DatabaseContextABC):
         UserRepoABC.__init__(self)
 
-        self._db: DatabaseContextABC = db_context
-
-    def create(self): pass
+        self._db_context: DatabaseContextABC = db_context
 
     def add_test_user(self):
         city = CityModel('Haren', '49733')
         city2 = CityModel('Meppen', '49716')
-        self._db.cursor.execute(city2.insert_string)
+        self._db_context.cursor.execute(city2.insert_string)
         user = UserModel('TestUser', city)
-        self._db.cursor.execute(user.insert_string)
+        self._db_context.cursor.execute(user.insert_string)
+        self._db_context.save_changes()
 
     def get_users(self) -> list[UserModel]:
-        self._db.cursor.execute(f"""SELECT * FROM `User`""")
-        return self._db.cursor.fetchall()
+        users =  []
+        results = self._db_context.select('SELECT * FROM `User`')
+        for result in results:
+            users.append(UserModel(result[1], self.get_city_by_id(result[2]), id = result[0]))
+        return users
 
     def get_cities(self) -> list[CityModel]:
-        self._db.cursor.execute(f"""SELECT * FROM `City`""")
-        return self._db.cursor.fetchall()
+        cities =  []
+        results = self._db_context.select('SELECT * FROM `City`')
+        for result in results:
+            cities.append(CityModel(result[1], result[2], id = result[0]))
+        return cities
+    
+    def get_city_by_id(self, id: int) -> CityModel:
+        if id is None:
+            return None
+        result = self._db_context.select(f'SELECT * FROM `City` WHERE `Id` = {id}')
+        return CityModel(result[1], result[2], id = result[0])

src/tests/custom/database/src/model/user_repo_abc.py

@@ -1,5 +1,6 @@
 from abc import ABC, abstractmethod
 
+from .city_model import CityModel
 from .user_model import UserModel
 
 
@@ -10,3 +11,9 @@ class UserRepoABC(ABC):
 
     @abstractmethod
     def get_users(self) -> list[UserModel]: pass
+    
+    @abstractmethod
+    def get_cities(self) -> list[CityModel]: pass
+    
+    @abstractmethod
+    def get_city_by_id(self, id: int) -> CityModel: pass