Dissertations can be based solely on the secondary data, without a need for the primary data. no research can be completed only using primary data and secondary data collection and analysis is compulsory for all dissertations.
Primary data collection methods can be divided into two categories: qualitative and quantitative.
Here you have to state that you have avoided misconducts during that research process and your dissertation is free from contradictions on ethical grounds and this statement must be true.
You can read more about ethical considerations here.
Positivism and phenomenology are the two main contrasting research philosophies related to business studies.
Positivism is an objective approach which relies on facts and quantitative data.
In simple words, research phislophy refers to your beliefe about how data should be collected, analysed and used.
Accordingly, clarification of reseaerch philosophy is a starting point for the choice of research methods.
Accordingly, findings of applised studies are valuable on practical levels and can be applied to address concrete problems.
Fundamental research, on the other hand, also known as basic research or pure research, aims to contribute to the overall scope of knowledge in the research area without immediate practical implications.