I stumbled upon a very brain-f**k error on Oracle 10g on these days.

Context: the following query [sql]SELECT * FROM (
SELECT TO_NUMBER(CUSTOMER_ID) AS SNDG FROM BAD_CODES_TABLE WHERE
AND I_LIKE=UPPER(‘STATIC_CONDITION’) AND CUSTOMER_ID NOT LIKE ‘%P%’ ) S WHERE TO_NUMBER(S.SNDG) >2000[/sql] could trigger a Invalid number if CUSTOMER_ID column contains invalid numbers.

Why?

Well…if you ask to “explain plan”, you will get something like

• a table full scan
  • Filter Predicates AND
    • I_LIKE=UPPER('STATIC_CONDITION')
    • TO_NUMBER(S.SNDG) >2000
    • CUSTOMER_ID NOT LIKE '%P%'

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How I Structure My Flask Applications Flask has been my preferred web framework as of late. I think it has a great core feature set and Armin, the main author, has done well to keep its API minimal and easy to digest even for developers that are relatively new to Python. However, given that it is a rather minimal framework, it can be often difficult to decide on how to structure an application after it reaches a certain level of complexity. It tends to be a common question that comes up in the #pocoo IRC channel.In this article I intend to share how I structure Flask applications. To help support this article Ive written a very basic application that Ive arbitrarily named Overholt. If you plan on following along I recommend having the source code open in your browser or a code editor.

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