Re: Database issues when adding GUI

> On Jun 7, 2021, at 11:07 AM, Rob Sargent <robjsargent(at)gmail(dot)com> wrote:
>
> On 6/7/21 9:02 AM, Rich Shepard wrote:
>> This is an unusual message and I hope someone(s) here can offer insights
>> into the cause of the problem I've been wrestling with for the past couple
>> of weeks.
>>
>> Context: For the past decade I've run my business tracking database from the
>> psql shell (currently with postgresql-12.2) and decided it's time to add a
>> frontend so it's a stand-alone desktop application. I'm learning to use
>> PyQt5 as the widget set and application framework.
>>
>> The database contains three lookup tables: activitytypes, industrytypes, and
>> statustypes, all have a single column and few rows. So I've started with
>> these to get python3 and PyQt5-5.13.2 to run the SELECT query and display
>> the results in a QTableView.
>>
>> The problem with all three is that my code produces an empty window and
>> hangs. There's no python error displayed and the application reports finding
>> the database but not the tables. For example, the activitytypes debugging
>> log contains:
>> INFO:root:found database
>> DEBUG:root:Defining model/view
>> DEBUG:root:model error: Unable to find table activitytypes
>> DEBUG:root:about to execute select query
>> DEBUG:root:End of Program
>>
>> I, and others on the python and pyqt mail lists and stackoverflow, can find
>> nothing wrong with the python code. This suggests it's something with the
>> database itself. But I have no idea where to look. The database structure
>> is:
>> bustrac=# \d
>> List of relations
>> Schema | Name | Type | Owner --------+---------------------------+----------+----------
>> public | activities | table | rshepard
>> public | activitytypes | table | rshepard
>> public | industrytypes | table | rshepard
>> public | locations | table | rshepard
>> public | organizations | table | rshepard
>> public | organizations_org_nbr_seq | sequence | rshepard
>> public | people | table | rshepard
>> public | people_person_nbr_seq | sequence | rshepard
>> public | projects | table | rshepard
>> public | statustypes | table | rshepard
>> (10 rows)
>>
>> What might stop a front-end application from finding a table that has been
>> readily accessed from the psql shell?
>>
>> All suggestions and recommendations are needed.
>>
>> TIA,
>>
>> Rich
>>
>> \
> This looks like a permissions problem, as though you are connecting as a role/user without permission to select from the tables.

I agree with Rich. Permissions, or you’re connecting as the wrong user. You might find it helpful to simplify and not use a GUI application until you get your connection issues sorted out. A simple command line Python app that connects to the database and prints the result of “select * from activitytypes limit 1” will enable quick(er) debugging of your connection issues.

Cheers
Philip