[dba-VB] Update gets string or binary truncation error

I am doing the update thing, updating data back to SQL Server.  I have 
been updating an ADO recordset in memory and when I try to update it 
back to SQL Server it throws an error that the update failed because it 
would cause a string value to be truncated.

How is this possible.  I thought that the table structure in memory 
mirrored the structure in the data store (SQL Server in this instance). 
  Doesn't the read of the data out of SQL Service discover the field 
size and type and build a similar structure in memory?

Apparently not, but if not how do I handle a case like this?
-- 
John W. Colby
www.ColbyConsulting.com