Using MySQL Meta Fields and Data

Imagine you have records with a field containing a UK Postcode (ZIP) code.
A typical UK Postcode is OX1 1AA or OX10 1BA but in fact in the software you also need just the Area Code part eg OX1 or OX10. Rather than parse out the Area Code dynamically in your code every time you need it why not store the Area Code in an additional meta-field. This makes for more elegant and more efficient code at the cost of a small amount of extra data. The additional advantage is that you can check for invalid postcode data at entry time.

Meta Fields such as this can be used for financial data which must be converted to a percentage etc.