Caché Parameter File Reference
User-Defined SQL Datatypes
InterSystems: The power behind what matters   
Class Reference   

Map SQL datatypes to their Caché equivalents.
[SqlUserDatatypes]    x=a
The [SqlUserDatatypes] section contains a user-defined datatype descriptions. Each description maps an SQL datatype to its Caché equivalent in the format x=a, as follows:
With the following line in the CPF file, when MYVARCHAR(10) is seen in a statement, the property is created with type %Library.String(MAXLEN=10,TRUNCATE=0).
Range of Values
As described above.
Management Portal
On the page System Administration > Configuration > SQL and Object Settings > User-defined DDL Mappings, select Create New User-defined DDL Mapping or Edit to modify list of mappings.