added initial implementation of the database class and the first exceptions regarding the database.

jwmudlib/database.py

@@ -0,0 +1,57 @@
+# This file is part of jwmud, written by Helmut Pozimski in 2014.
+#
+#       jwmud is free software: you can redistribute it and/or modify
+#       it under the terms of the GNU General Public License as published by
+#       the Free Software Foundation, version 2 of the License.
+#
+#       jwmud is distributed in the hope that it will be useful,
+#       but WITHOUT ANY WARRANTY; without even the implied warranty of
+#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#       GNU General Public License for more details.
+#
+#       You should have received a copy of the GNU General Public License
+#       along with jwmud.  If not, see <http://www.gnu.org/licenses/>.
+
+# -*- coding: utf8 -*-
+
+import sqlite3
+
+from jwmudlib import jwmu_exceptions
+
+
+class db:
+    def __init__(self, db_path):
+        """Constructor, establishes the initial connection to the database."""
+        try:
+            self.__connection = sqlite3.connect(db_path)
+        except sqlite3.OperationalError:
+            raise jwmu_exceptions.DataBaseAccessFailed()
+        else:
+            self.__cursor = self.__connection.cursor()
+
+    def __del__(self):
+        """Destructor, closes the connection to the database"""
+        self.__connection.close()
+
+    def __ExecuteQuery(self, query, arguments=None):
+        """Executes any query and returns the result"""
+        if arguments is None:
+            query_result = self.__cursor.execute(query)
+        else:
+            query_result = self.__cursor.execute(query, arguments)
+        return query_result
+
+    def __ExecuteStatement(self, statement, arguments=None):
+        """Executes any statements that perform a write access to the
+        database
+
+        """
+        try:
+            if arguments is None:
+                self.__cursor.execute(statement)
+            else:
+                self.__cursor.execute(statement, arguments)
+        except sqlite3.OperationalError:
+            raise jwmu_exceptions.DataBaseWriteFailed()
+        else:
+            self.__connection.commit()

jwmudlib/jwmu_exceptions.py

@@ -0,0 +1,32 @@
+# This file is part of jwmud, written by Helmut Pozimski in 2014.
+#
+#       jwmud is free software: you can redistribute it and/or modify
+#       it under the terms of the GNU General Public License as published by
+#       the Free Software Foundation, version 2 of the License.
+#
+#       jwmud is distributed in the hope that it will be useful,
+#       but WITHOUT ANY WARRANTY; without even the implied warranty of
+#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#       GNU General Public License for more details.
+#
+#       You should have received a copy of the GNU General Public License
+#       along with jwmud.  If not, see <http://www.gnu.org/licenses/>.
+
+# -*- coding: utf8 -*-
+
+
+class DataBaseAccessFailed(Exception):
+    def __init__(self):
+        self.__message = "Accessing the database failed!"
+
+    def __str__(self):
+        return self.__message
+
+
+class DataBaseWriteFailed(Exception):
+    def __init__(self):
+        self.__message = "Writing to the database failed, requested action " \
+                         "aborted !"
+
+    def __str__(self):
+        return self.__message