From a technical perspective, the built-in data type NUMC describes objects of the type CHAR with a
maximum length of 255 characters. It is intended for numerical texts. This is not checked however when
writing to or reading from database fields of this type. Automatic checks are only made for dynpro fields
typed with reference to NUMC. In ABAP, NUMC is assigned to the special type n and the associated rules apply.
From a technical perspective, the data type CLNT describes objects of the type CHAR with length 3. If the data type CLNT is used for the first key field of a database table, this makes the database table
client-specific.
From a technical perspective, the predefined data type LANG describes objects of the type CHAR with
length 1. It is intended specifically for language keys. A component of structures or database tables
that has the data type LANG can be identified as text language. The text language is used to convert character-like components of the structure when importing data from
data clusters and in the binary
RFC protocol for passing TABLES parameters between
MDMP systems and
Unicode systems. The
primary key of a
text table is still made up of the
foreign key and a field of type LANG.
When the statements WRITE or WRITE TO are used to represent a
dynpro field with the
type LANG (and when a field that references this type is formatted), this field has an output length of 2 and is converted automatically from the single-character internal language ID to the matching two-character ISO ID using the
conversion routine ISOLA (and back).