choice of web-framework

[John Black]

In article <mailman.50.1508843658.2821.python-list at python.org>, 
rosuav at gmail.com says...
> 
> On Tue, Oct 24, 2017 at 6:57 AM, Chris Warrick <kwpolska at gmail.com> wrote:
> > On 23 October 2017 at 21:37, John Black <jblack at nopam.com> wrote:
> >> Chris, thanks for all this detailed information.  I am confused though
> >> with your database recommendation.  You say you teach SQLAlchemy but
> >> generally use PostgreSQL yourself.  I can maybe guess why there seems to
> >> be this contradiction.  Perhaps PostgreSQL is better but too advanced for
> >> the class you are teaching?  Can you clarify on which you think is the
> >> better choice?  Thanks.
> >
> > Different Chris, but I?ll answer. Those are two very different things.
> >
> > PostgreSQL is a database server. It talks SQL to clients, stores data,
> > retrieves it when asked. The usual stuff a database server does.
> > Alternatives: SQLite, MySQL, MS SQL, Oracle DB, ?
> >
> > SQLAlchemy is an ORM: an object-relational mapper, and also a database
> > toolkit. SQLAlchemy can abstract multiple database servers/engines
> > (PostgreSQL, SQLite, MySQL, etc.) and work with them from the same
> > codebase. It can also hide SQL from you and instead give you Python
> > classes. If you use an ORM like SQLAlchemy, you get database support
> > without writing a single line of SQL on your own. But you still need a
> > database engine ? PostgreSQL can be one of them. But you can deploy
> > the same code to different DB engines, and it will just work?
> > (assuming you didn?t use any DB-specific features). Alternatives:
> > Django ORM.
> >
> > psycopg2 is an example of a PostgreSQL client library for Python. It
> > implements the Python DB-API and lets you use it to talk to a
> > PostgreSQL server. When using psycopg2, you?re responsible for writing
> > your own SQL statements for the server to execute. In that approach,
> > you?re stuck with PostgreSQL and psycopg2 unless you rewrite your code
> > to be compatible with the other database/library. Alternatives (other
> > DBs): sqlite3, mysqlclient. There are also other PostgreSQL libraries
> > available.
> >
> 
> Thanks, namesake :)
> 
> The above is correct and mostly accurate. It IS possible to switch out
> your back end fairly easily, though, even with psycopg2; there's a
> standard API that most Python database packages follow. As long as you
> stick to standard SQL (no PostgreSQL extensions) and the standard API
> (no psycopg2 extensions), switching databases is as simple as changing
> your "import psycopg2" into "import cx_oracle" or something. (And,
> most likely, changing your database credentials.)
> 
> The point of an ORM is to make your databasing code look and feel like
> Python code, rather than manually crafting SQL statements everywhere.
> Here's how a simple database operation looks in SQLAlchemy:

Thank you Chris and Chris!

John Black