Setting Max Length for an XML element

Hi all. I'm involved in a project where we're using, and making a few extensions to, the IMS metadata schemas.

One thing I'm wondering about is how one would set the maximum length for data to be stored in an xml element?

I'm looking through the IMS specs for their metadata tags, and I see many references to LangStringType (n chars) but I can find no reference to the length of LangStringType in the schema definition.

It seems to me that the LangStringType (n chars) is arbitrarily set, and the length of the string when inserting into the database must be verified independently of any XML structures

Can anyone provide any advice here? Am I close, or am I way off base? I'm very new to XML, so any help is greatly appreciated.

Thanks in advance,
Pablo