Download Safari Books Online apps: Apple iOS | Android

Entire Site

Safari Books Online

    Free Trial

    Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.


    Copyright
    Preface
    Ch. 1. Text
    Ch. 2. Files
    Ch. 3. Time and Money
    Ch. 4. Python Shortcuts
    Ch. 5. Searching and Sorting
    Ch. 6. Object-Oriented Programming
    Ch. 7. Persistence and Databases
    Ch. 8. Debugging and Testing
    Ch. 9. Processes, Threads, and Synchronization
    Ch. 10. System Administration
    Ch. 11. User Interfaces
    Ch. 12. Processing XML
    Ch. 13. Network Programming
    Ch. 14. Web Programming
    Ch. 15. Distributed Programming
    Ch. 16. Programs About Programs
    Ch. 17. Extending and Embedding
    Ch. 18. Algorithms
    Ch. 19. Iterators and Generators
    Introduction
    Recipe 19.1. Writing a range-like Function with Float Increments
    Recipe 19.2. Building a List from Any Iterable
    Recipe 19.3. Generating the Fibonacci Sequence
    Recipe 19.4. Unpacking a Few Items in a Multiple Assignment
    Recipe 19.5. Automatically Unpacking the Needed Number of Items
    Recipe 19.6. Dividing an Iterable into n Slices of Stride n
    Recipe 19.7. Looping on a Sequence by Overlapping Windows
    Recipe 19.8. Looping Through Multiple Iterables in Parallel
    Recipe 19.9. Looping Through the Cross-Product of Multiple Iterables
    Recipe 19.10. Reading a Text File by Paragraphs
    Recipe 19.11. Reading Lines with Continuation Characters
    Recipe 19.12. Iterating on a Stream of Data Blocks as a Stream of Lines
    Recipe 19.13. Fetching Large Record Sets from a Database with a Generator
    Recipe 19.14. Merging Sorted Sequences
    Recipe 19.15. Generating Permutations, Combinations, and Selections
    Recipe 19.16. Generating the Partitions of an Integer
    Recipe 19.17. Duplicating an Iterator
    Recipe 19.18. Looking Ahead into an Iterator
    Recipe 19.19. Simplifying Queue-Consumer Threads
    Recipe 19.20. Running an Iterator in Another Thread
    Recipe 19.21. Computing a Summary Report with itertools.groupby
    Ch. 20. Descriptors, Decorators,and Metaclasses
    Colophon
    Index
    • Create BookmarkCreate Bookmark
    • Create Note or TagCreate Note or Tag
    • DownloadDownload
    • PrintPrint
    Share this Page URL
    Help

    Chapter 19. Iterators and Generators > Fetching Large Record Sets from a Databa...

    Recipe 19.13. Fetching Large Record Sets from a Database with a Generator

    Credit: Christopher Prinos

    19.14.1. Problem

    You want to fetch a result set from a database (using the Python DB API) and easily iterate over each record in the result set. However, you don't want to use the DB cursor's method fetchall: it could consume a lot of memory and would force you to wait until the whole result set comes back before you can start iterating.


      

    You are currently reading a PREVIEW of this book.

                                                                                            

    Get instant access to over
    $1 million worth of books and videos.

      

    Start a Free Trial