Posted by Data types in different environments have different names. Data types in SSIS environment is different from names in system namespace in Microsoft .NET framework.
In data flow of SSIS, maybe we need to use the compenents to convert data types when moving them from sources to destinations.
Here is some sources:
Mapping Data Types in the Data Flow
Also, here are some cheat sheets about data types in SQL Server and SSIS:
String data types:
Integer and Boolean:
Other data types:
Day/time data types:
Floating point data types:
