Hi Community!

I'm currently customizing reinstalling my Odoo database as I've been getting a recursion error on my previous database. I requested a reinstall of Odoo from my VPS provider. After reinstallation of the VPS, I installed a backup of my database. Everything seemed ok but then now I cannot install any app or module as it's giving me an error everytime I try to install any app or module. I'm a total beginner in setting up Odoo but everything seems to be straight forward so I think I can follow your suggestions if instructed. 

Here's the error log of the problem I encountered. I appreciate any help from you guys. Thank you very much!

Error: 
Odoo Server Error

Traceback (most recent call last):
File "/opt/odoo12/odoo/odoo/http.py", line 656, in _handle_exception
return super(JsonRequest, self)._handle_exception(exception)
File "/opt/odoo12/odoo/odoo/http.py", line 314, in _handle_exception
raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
File "/opt/odoo12/odoo/odoo/tools/pycompat.py", line 87, in reraise
raise value
File "/opt/odoo12/odoo/odoo/http.py", line 698, in dispatch
result = self._call_function(**self.params)
File "/opt/odoo12/odoo/odoo/http.py", line 346, in _call_function
return checked_call(self.db, *args, **kwargs)
File "/opt/odoo12/odoo/odoo/service/model.py", line 97, in wrapper
return f(dbname, *args, **kwargs)
File "/opt/odoo12/odoo/odoo/http.py", line 339, in checked_call
result = self.endpoint(*a, **kw)
File "/opt/odoo12/odoo/odoo/http.py", line 941, in __call__
return self.method(*args, **kw)
File "/opt/odoo12/odoo/odoo/http.py", line 519, in response_wrap
response = f(*args, **kw)
File "/opt/odoo12/odoo/addons/web/controllers/main.py", line 966, in call_button
action = self._call_kw(model, method, args, {})
File "/opt/odoo12/odoo/addons/web/controllers/main.py", line 954, in _call_kw
return call_kw(request.env[model], method, args, kwargs)
File "/opt/odoo12/odoo/odoo/api.py", line 759, in call_kw
return _call_kw_multi(method, model, args, kwargs)
File "/opt/odoo12/odoo/odoo/api.py", line 746, in _call_kw_multi
result = method(recs, *args, **kwargs)
File "<decorator-gen-61>", line 2, in button_immediate_install
File "/opt/odoo12/odoo/odoo/addons/base/models/ir_module.py", line 74, in check_and_log
return method(self, *args, **kwargs)
File "/opt/odoo12/odoo/odoo/addons/base/models/ir_module.py", line 445, in button_immediate_install
return self._button_immediate_function(type(self).button_install)
File "/opt/odoo12/odoo/odoo/addons/base/models/ir_module.py", line 561, in _button_immediate_function
modules.registry.Registry.new(self._cr.dbname, update_module=True)
File "/opt/odoo12/odoo/odoo/modules/registry.py", line 86, in new
odoo.modules.load_modules(registry._db, force_demo, status, update_module)
File "/opt/odoo12/odoo/odoo/modules/loading.py", line 421, in load_modules
loaded_modules, update_module, models_to_check)
File "/opt/odoo12/odoo/odoo/modules/loading.py", line 313, in load_marked_modules
perform_checks=perform_checks, models_to_check=models_to_check
File "/opt/odoo12/odoo/odoo/modules/loading.py", line 195, in load_module_graph
registry.init_models(cr, model_names, {'module': package.name})
File "/opt/odoo12/odoo/odoo/modules/registry.py", line 301, in init_models
func()
File "/opt/odoo12/odoo/odoo/models.py", line 282, in _reflect
self.env['ir.model.fields']._reflect_model(self)
File "/opt/odoo12/odoo/odoo/addons/base/models/ir_model.py", line 879, in _reflect_model
for name in to_xmlids
File "/opt/odoo12/odoo/odoo/addons/base/models/ir_model.py", line 1539, in _update_xmlids
self.env.cr.execute(query, [arg for row in sub_rows for arg in row])
File "/opt/odoo12/odoo/odoo/sql_db.py", line 148, in wrapper
return f(self, *args, **kwargs)
File "/opt/odoo12/odoo/odoo/sql_db.py", line 225, in execute
res = self._obj.execute(query, params)
psycopg2.ProgrammingError: there is no unique or exclusion constraint matching the ON CONFLICT specification