If your scenario is simple enough and you've bound your form to the database,
you can do this without writing any code (except for in formulas). I've
written a "recipe" describing how to sequentially page through an Access
database table using rules and filters, and posted it
(http://enterprise-solutions.swits.net/infopath/sequential-db-table-record-naviga
tion.htm).
Converting this solution to use a SQL Server table shouldn't be a problem.

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S.Y.M. Wong-A-Ton