diff --git a/ITPlanning/app.py b/ITPlanning/app.py
index 01d181a..f73b59f 100644
--- a/ITPlanning/app.py
+++ b/ITPlanning/app.py
@@ -4,8 +4,8 @@ from logging.handlers import TimedRotatingFileHandler
 from flask import Flask
 from pony.flask import Pony
 from ITPlanning.api import api
-from ITPlanning.db import init_database, release_database
 #from ITPlanning.frontend import frontend
+from ITPlanning.db import init_database
 from ITPlanning.config import IniConfig
 logger = logging.getLogger("ITPlanning")
 
diff --git a/ITPlanning/db.py b/ITPlanning/db.py
index ca16157..fac4267 100644
--- a/ITPlanning/db.py
+++ b/ITPlanning/db.py
@@ -2,28 +2,30 @@
 
 from datetime import datetime
 from urllib.parse import urlparse, parse_qsl
-from pony.orm import Database, Required, Optional, Set, PrimaryKey, LongStr
+from pony.orm import Database, Required, Optional, Set, PrimaryKey, LongStr, Json
+from pony.orm import DatabaseError
 
 db = Database()
 
+
 class Service(db.Entity):
     id = PrimaryKey(int, auto=True)
     name = Required(str, unique=True)
     localisation = Optional(str)
     max_appointement = Required(int)
-    plannings = Set('Planning')
-    service_category = Required('Service_category')
-    appointments = Set('Appointment')
+    plannings = Set("Planning")
+    service_category = Required("Service_category")
+    appointments = Set("Appointment")
     description = Optional(str)
 
 
 class Planning(db.Entity):
     id = PrimaryKey(int, auto=True)
     name = Required(str, unique=True)
-    working_plan = Required(LongStr)
+    working_plan = Required(Json)
     services = Set(Service)
-    appointments = Set('Appointment')
-    planners = Set('Planner')
+    appointments = Set("Appointment")
+    planners = Set("Planner")
 
 
 class Setting(db.Entity):
@@ -41,8 +43,8 @@ class Appointment(db.Entity):
     is_unavaillable = Required(bool)
     service = Required(Service)
     planning = Required(Planning)
-    ticket = Optional('Ticket')
-    customer = Optional('Customer')
+    ticket = Optional("Ticket")
+    customer = Optional("Customer")
     notes = Optional(LongStr)
 
 
@@ -54,7 +56,7 @@ class Customer(db.Entity):
     localisation = Optional(str)
     mobile_number = Optional(str)
     phone_number = Optional(str)
-    tickets = Set('Ticket')
+    tickets = Set("Ticket")
     appointments = Set(Appointment)
     notes = Optional(str)
 
@@ -62,7 +64,7 @@ class Customer(db.Entity):
 class Ticket(db.Entity):
     id = PrimaryKey(int, auto=True)
     ref = Optional(str, unique=True)
-    service_category = Required('Service_category')
+    service_category = Required("Service_category")
     customer = Required(Customer)
     appointment = Required(Appointment)
     notes = Optional(str)
@@ -83,6 +85,7 @@ class Planner(Customer):
     password = Required(str)
     is_admin = Optional(bool)
 
+
 def parse_uri(database_uri):
     if not isinstance(database_uri, str):
         raise TypeError("Expecting a string")
@@ -122,10 +125,16 @@ def parse_uri(database_uri):
         )
     return dict()
 
+
 def init_database(database_uri):
     settings = parse_uri(database_uri)
     db.bind(**settings)
-    db.generate_mapping(create_tables=True)
+    db.generate_mapping(check_tables=False)
+    try:
+        db.check_tables()
+    except DatabaseError:
+        db.create_tables()
+
 
 def release_database():
     db.disconnect()