Sunday, April 10, 2011

not-null when creating table

Null values mess up numeric aggregates. If you often do that then consider a meaningful default value, though it distorts average().

Nulls mess up composite boolean exp. Worse still, nulls can even mess up basic where-clause.

My first choice is not-null.
- For string fields, default to empty string.
- For integer date fields, wall street systems often default to 99991231.

In terms of null handling, SQL beats java. As java developers going into SQL, we don't need to be too paranoid about nulls.


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