Implementing database class

database.py

@@ -0,0 +1,79 @@
+from flask_mysqldb import MySQL
+
+class DB(object):
+	"""docstring for DB"""
+	def __init__(self, app):
+		super (DB, self).__init__()
+		try:
+			self.mysql = MySQL(app)
+			self.cursor = None
+			self.connected = True
+		except:
+			self.connected = False
+
+	def select(self, sql_string, args = None, quantity = "one"):
+		try:
+			self.cursor = self.mysql.connection.cursor()
+			self.cursor.execute(sql_string, args)
+			retult = 0
+			if (quantity == "one"):
+				result = self.cursor.fetchone()
+			else:
+				result = self.cursor.fetchall()
+			self.cursor.close()
+			return (result)
+		except Exception as e:
+			print(e)
+			return -1
+
+	#used to call a database stored procedure
+	def callproc(self, procName, args, quantity = "one"):
+		try:
+			self.cursor = self.mysql.connection.cursor()
+			self.cursor.callproc(procName, args)
+			if (quantity == "one"):
+				result = self.cursor.fetchone()
+			else:
+				result = self.cursor.fetchall()
+			self.cursor.close()
+			return (result)
+		except Exception as e:
+			print(e)
+			return -1
+
+	#insert and update are duplicated methods for the sake of readability and in case we want to add specific behaviour to one of the operations
+	#they return the number of affected rows
+	def insert(self, sql_string, args = None):
+		try:
+			self.cursor = self.mysql.connection.cursor()
+			self.cursor.execute(sql_string, args)
+			result = self.cursor.rowcount
+			self.mysql.connection.commit()
+			self.cursor.close()
+			return (result)
+		except Exception as e:
+			print(e)
+			return -1
+
+	def update(self, sql_string, args = None):
+		try:
+			self.cursor = self.mysql.connection.cursor()
+			self.cursor.execute(sql_string, args)
+			result = self.cursor.rowcount
+			self.mysql.connection.commit()
+			self.cursor.close()
+			return (result)
+		except Exception as e:
+			print(e)
+			return -1
+
+	def close(self):
+		self.mysql.connection.close()
+		return (None)
+
+#implement the singleton logic for the database class
+_DB = None
+
+def NewConexion(app):
+	global _DB
+	_DB = DB(app)