In the source code for each supported dialect below, you will see calls to registerColumnType(type, String).
The type is a java.sql.Types constant, and String can represent the supported database type for the database.
Additionally, you may see calls to registerColumnType(type, int, String) where the int is a maximum length for
this mapping. When no maximum length is specified this is the "default" mapping. If a source database contains
a field whose length exceeds any destination type mapping, the "default" mapping is used.