Introduction to SQL Alchemy - SyPy June 2013
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The document summarizes a presentation on SQLAlchemy by Roger Barnes at the PyCon conference in June 2013, highlighting its features as a Python SQL toolkit and object-relational mapper. It compares SQLAlchemy with Django's ORM, noting that while both have their merits, SQLAlchemy is more flexible and suitable for a broader range of applications. The presentation also outlines the core structure and functionality of SQLAlchemy, including session management and mapping between domain objects and database rows.
Introduction to SQL Alchemy - SyPy June 2013
- 1. SyPy June 2013 ● Introduction to SQLAlchemy - Roger Barnes ● Using Robot Framework for testing, communication and world domination - Dylan Jay ● Configuration management with Salt Stack - Daniel Bryan ● + lightning talks ● Pub
- 3. SyPy June 2013 Next SyPy - Aug 1, 2013 http://bit.ly/11kHTmB
- 4. Introduction to SQLAlchemy Roger Barnes SyPy June 2013 [email protected] @mindsocket
- 5. About Me 15 years software development 4 years Python/Django 4 months SQLAlchemy
- 6. SQLAlchemy is... Python SQL toolkit & Object Relational Mapper
- 7. About SQLAlchemy ● Full featured ● Mature, robust, documented, maintained ● Flexible – Use what you need – Extend when you need – Database oriented – Doesn't dictate schema design – ...
- 8. Enterprise!
- 9. DB support ● SQLite ● Postgresql ● MySQL ● Oracle ● MS-SQL ● Firebird ● Sybase ● ...
- 10. Python support cPython 2.5+ cPython 3+ Jython 2.5+ Pypy 1.5+
- 11. Compared with Django ORM? ● Both are good ● Key philosophical design difference Django → Web applications SQLAlchemy → Database applications
- 12. Compared with Django ORM? ● Django ORM – easier to learn – less flexible – well suited for most web apps – comes with a free admin app
- 13. Compared with Django ORM? ● SQLAlchemy – harder to learn (but only a little) – massively flexible – suited to a wider range of applications, especially those that benefit from the power of an RDBMS
- 14. Project Structure SQLAlchemy is like an onion... … or a cake
- 15. Structure
- 16. Core ● Abstraction over Python's DBAPI ● SQL language via generative Python expressions
- 17. Core ● Good for DB performance – bulk operations – complex queries – fine-tuning – connection/tx management
- 18. Core ● Schema – Managed by a Metadata object – Declare tables, columns and other attributes – Closely aligned with Data Definition Language
- 19. Core ● SQL Expressions – INSERT, UPDATE, DELETE – SELECT, joins, grouping – Functions, expressions, operators ● Connection pooling ● Backend DB dialects
- 20. Demo
- 21. ORMs in General ● Simple case – translate between a domain object and a table row ● More complex – arbitrary rows mapped to an object ● Handle relationships
- 22. ORMs in General ● Query in terms of objects ● Represent class inheritance ● Data validation
- 23. SQLAlchemy ORM ● Layer on top of core ● Session based ● Session manages object state
- 24. SQLAlchemy ORM ● 2 ways to use – Classical Mapping ● Define table ● Define object ● Configure mapper – Modern - Declarative ● Shorthand combining table metadata and class mapping ● Similar to Django ORM
- 25. Demo
- 26. Questions? ● Other resources – SQLAlchemy - http://sqlalchemy.org/ – Longer (better) introduction - http://bit.ly/13UQXVV ● Contact [email protected] @mindsocket