Platform-independent user-defined functions for data access

The disclosed embodiments provide a system for processing data. During operation, the system obtains a user-defined function (UDF) that is defined using a standard UDF interface for accessing multiple platforms. Next, the system converts data in a platform into a standard form that is supported by the standard UDF interface using a platform-specific wrapper for the UDF and a platform-specific implementation of the standard UDF interface. The system then generates output data in the standard form by applying one or more operations to the data in the standard form. Finally, the system converts the output data into a platform-specific form that is supported by the platform and returns the output data in the platform-specific form.