Because of the large numbers of database management systems and datatypes involved, Connect CDC Director does not record every possible datatype combination. Instead, the Connect CDC Director classifies SQL datatypes into several categories, and in some categories, also assigns a length to the datatype. The categories are then used to determine whether the datatypes are compatible.
Connect CDC Director prohibits invalid mappings and warns of mappings that may cause truncation or be incompatible at distribution time. Most of the mappings subject to warning are “wide to narrow” mappings, where the character length, numeric length, numeric scale, or numeric precision of the sending column’s datatype is greater than that of the receiving column.
Connect CDC Kernel packages the data for sending and, in “wide to narrow” cases, truncates the data according to the rules described in Data handling.
This section introduces the datatype categories and describes by category the individual datatype mappings supported by Connect CDC.