1. A system for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said data importing and exporting system comprising: datalist generating means for generating datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported and exported between external computing environment and the object oriented computing environment; metadata generating means for generating a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters; importing means, responsive to a request from said external computing environment to import external data into said object oriented computing environment, for identifying an object oriented computing environment attribute from said datalist objects and for identifying a corresponding metadata object, and for applying the alternate conversion parameters in said corresponding metadata object to said external data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data and place said object oriented data into a corresponding data object which is associated with said corresponding metadata object; and exporting means, responsive to a request from said object oriented computing environment to export object oriented data from an object in said object oriented computing environment to said external computing environment, for identifying a metadata object corresponding to said object and for identifying said external data name corresponding to said metadata object from said datalist, and for applying the alternate conversion parameters in the corresponding metadata object to said object oriented data from said object if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert object oriented data into external data.