Update sql.py

[igorvoltaic]

Functionality which commits changes to Postgres DB
https://www.postgresql.org/docs/8.3/sql-commit.html

[kzidane]

What are you trying to do exactly, @igorvoltaic?

[igorvoltaic]

Hi Kareem,

I've been following the guide to deploy my app to Heroku and spent quite some time trying to understand why non of the changes to Prostges are persistent

Here is an example:

Python 3.7.6 (default, Mar  6 2020, 22:15:44) 
[Clang 11.0.0 (clang-1100.0.33.17)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from cs50 import SQL
>>> db = SQL("postgres://URI?sslmode=require")
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[]
>>> db.execute("INSERT INTO warehouses (name, address, status) VALUES (:name, :address, :status);", name='wh-1', address='add-1', status=1)
1
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[{'id': 1, 'name': 'wh-1', 'address': 'add-1', 'status': 1}]
>>> 
>>> 
>>> 
>>> 
>>> db = SQL("postgres://URI?sslmode=require")
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[]
>>>

Turns out you need to issue COMMIT statement for changes to be persistent in Postgres.

Also Travis tells me I need to do more testing first :)

[igorvoltaic]

Just checked the lib (sql.py) locally, everything works as intended:

Python 3.7.6 (default, Mar  6 2020, 22:15:44) 
[Clang 11.0.0 (clang-1100.0.33.17)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from sql import SQL
>>> db = SQL("postgres://URI?sslmode=require")
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[]
>>> db.execute("INSERT INTO warehouses (name, address, status) VALUES (:name, :address, :status);", name='wh-1', address='add-1', status=1)
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[{'id': 2, 'name': 'wh-1', 'address': 'add-1', 'status': 1}]
>>> 
>>> 
>>> 
>>>
>>> db = SQL("postgres://URI?sslmode=require")
>>> warehouses = db.execute("SELECT id, name, address, status FROM warehouses")
>>> warehouses
[{'id': 2, 'name': 'wh-1', 'address': 'add-1', 'status': 1}]
>>> 

[dmalan]

Thank you for catching this, @igorvoltaic. We're about to deploy a broader set of changes to handle transactions more robustly!

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