Oracle database applications can be run against non-Oracle database servers using SQL*Connect or the
Oracle Transparent Gateway. In such cases, the format of rowids varies according to the
characteristics of the non-Oracle system. Furthermore, no standard translation to
VARCHAR2/hexadecimal format is available. Programs can still use the ROWID datatype. However, they
must use a nonstandard translation to hexadecimal format of length up to 256 bytes.

Rowids of a non-Oracle database can be stored in a column of the UROWID datatype.