Mapping Columns of Different Data Types and Lengths

If the data types and/or lengths of the Table instance and Table Descriptor Columns do not match, mapping may still be allowed. The rules are different for source and target Table Descriptors.

See Figure 3-3 for an illustration of the data flow.

The principles are:

• Only Number data types can feed into Number data types and only Date data types can feed into Date data types.

• Shorter lengths can feed into longer lengths, but longer lengths cannot feed into shorter lengths.

• For Number data types, lesser precision can feed into greater precision, but greater precision cannot feed into lesser precision.

• On the source side, Table instance Columns of Number and Date data types can feed into Table Descriptor Column Varchar2 data types.

• On the target side, Table Descriptor Column Number data types can feed into Table instance Column Varchar2 data types, but Date data types cannot.