Hi, are Office 2010 Infopath going to introduce an easy way to strengthen security on text fields, in Office 2007, any sign is allowed in a text field. It is however posible to prohibid a sign using rules, however that takes a lot of time. To secure a text filed so it can not be use to parse SQL code to a database, you need to make quit a few rules to stop special signs for being transmitted, one rule for each sign.
A simple solution for this would be a check box parameter on text fields data tab "No special signs allowed" so it is not possible to run SQL code agains a database, and it is optional for the user.