The principle of any retrospective on patient data based investigation is searching the patients by problem or sign, but no name. With a proper, by problem encoded computer archived database, the datamining process would be easy. One would need only input the request and get the proper data in short time.

The medical archives frequently base on paper records only, with patient name as entering key. To find the proper record in such archive, detective strategy is needed. The process continues with collecting the usually enormous amount of papers, finding between them the appropriate records and finally encoding and arranging them in table. The whole named process can be separated on patients, paper and data mining. Because of their dilatory, these phases can be the most time loosing part of non-medical data based investigation. Author describes his data mining experience.