June 2010
Intermediate to advanced
328 pages
7h 51m
English
Content preview from SQL Antipatterns
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Chapter 19Implicit Columns
How can I tell what I think till I see what I say?
E. M. Forster
A PHP programmer asked for help troubleshooting the confusing result of a seemingly straightforward SQL query against his library database:
| Implicit-Columns/intro/join-wildcard.sql | |
| | SELECT * FROM Books b JOIN Authors a ON (b.author_id = a.author_id); |
This query returned all book titles as null. Even stranger, when he ran a different query without joining to the Authors, the result included the real book titles as expected.
I helped him find the cause of his trouble: the PHP database extension he was using returned each row resulting from the SQL query as an associative array. For example, he could access the Books.isbn column as $row["isbn"] ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.