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Python SQLAlchemy Basics Working with SQLAlchemy Analyze Books

Andy McDonald
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Andy McDonald
Python Development Techdegree Graduate 13,801 Points
Posted by Andy McDonald
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Andy McDonald
Python Development Techdegree Graduate 13,801 Points

Why do I query the class name?

It doesn't fully make sense to me why I am querying the class name, not the table, or the DB its saved to. It makes more sense to me to query one of the latter. I get that its linked to the DB with the declarative base but in my mind its like querying 'item' in 'list', I guess that's just the way it is? Is there something that slipped passed me that would help me conceptualize this better?

https://teamtreehouse.com/library/analyze-books

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

Quick answer: the session is the link to the database and Book allows reference to the class attribute Book.__tablename__ that has the value “books”.

  • So the query is run on the “books” table.
  • The order_by returns the ordered list of books (like a list), then
  • first() selects the first item (like books[0]).