listi.net

External Data

This is data you don't control.

You usually expect it in some format or pattern.

From an external file

from a database

from a screen scrape

Beginner

Assumes data is in that pattern

Hardcoding of column numbers

Medium

Checks the data before processing to make sure it's in the right pattern

Look for expected columns and handle if missing

reference a column variable instead of the column number

Break the code if column is missing

Advanced

Has rules to govern checking and reporting if data format has changed.