Having used seam-gen to create my beans from an existing schema, on deploying the ear, I got messages along the lines of "Wrong column type: PROJECT, expected: varchar(3)". So I guessed Seam (or Hibernate) is having trouble mapping back the beans to the schema so I changed all the CHAR fields to VARCHAR (even those of length 1). Then it complained, wanting one (but not all !?) of the VARCHAR(1)s as CHAR(1)s so I obliged (luckily I was using a test database that I can tweak the schema of on this occasion). Now I have the app deployed. Any ideas what caused this and what best practice is (especially when the schema is not going to change) ?