Firstly, How would you get Google Alerts information into a database other than to parse the text of the email message that Google sends you?
It seems that there is no Google Alerts API.
If you must parse text, how would you go about parsing out the relevant pieces of the email message?
When you create the alert, set the "Deliver To" to "Feed" and then you can consume the feed XML as you would any other feed. This is much easier to parse and digest into a database.