U2 Developer Works Article: Validate data types in U2 using XML schema.
U2 stores all of its data without any type validation. Thus
the same field can contain an integer, a string, or even an
internal date structure. While this may be useful to the
application developer, it can cause problems when integrating the
data from your U2 environment to an external environment. In this
article, validate the data against a schema and prevent invalid
data with update triggers.