Book cover

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  1. Introduction
  2. Objects and Classes
  3. Finding Duplicate Files
  4. Matching Patterns
  5. Parsing Text
  6. Running Tests
  7. An Interpreter
  8. Functions and Closures
  9. Protocols
  10. A File Archiver
  11. An HTML Validator
  12. A Template Expander
  13. A Code Linter
  14. Page Layout
  15. Performance Profiling
  16. Object Persistence
  17. Binary Data
  18. A Database
  19. A Build Manager
  20. A Package Manager
  21. Transferring Files
  22. Serving Web Pages
  23. A File Viewer
  24. Undo and Redo
  25. A Virtual Machine
  26. A Debugger
  27. Observers
  28. Generating Documentation
  29. Search
  30. File Compression
  31. A File Cache
  32. A Query Builder
  33. Concurrency
  34. Conclusion
  1. Bibliography
  2. Bonus Material
  3. Syllabus
  4. License
  5. Code of Conduct
  6. Contributing
  7. Glossary
  8. Colophon
  9. Index

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GitHub repository

A Query Builder

  • FIXME

Terms defined: active record, Build manager

FIXME: create query builder

Issue 45

  • SQL requires parts of query in an odd order
  • So create active records using the Builder pattern
  • Does not scale up to more complex queries
    • Have to build an expression tree in memory and rearrange clauses for that
  • Thanks to Mike Bayer for advice
  • select_all.py: get all rows of table using reflection to get table name
  • get_metadata.py: cache table description and convert row tuples to dictionaries
  • simpler_metadata.py: let SQLite do that
  • choose_columns.py: select columns using immediate string formatting
    • test get-all case as well as getting specific columns
    • exercise: re-introduce cached metadata to do error handling
  • delay_columns.py: have query save the column names for later use in run method
    • complicates things now, but becomes useful later
  • aggregate.py: add aggregation
    • columns can now be string or aggregates
    • exercise: add group-by
  • insert.py: insert values
    • go back to keeping metadata in class (which may add startup overheads for large programs)
    • exercise: handle insertion of multiple records
    • exercise: handle insertion of objects with appropriately-named fields