Clinical research data are typically collected and stored in relational databases as part of the healthcare process (e.g. Electronic Patient Files) or in dedicated scientific data capturing systems.
Your data capturing system must allow for:
Your data capturing system (whether manual data entry from paper, via electronic forms, or sophisticated real-time connections between the primary source data and the study database) should be able to assess and report the logical consistency and the clinical probability of data values. Note that for clinical trials, registering the reason for any modification after initial entry of a data element is mandatory. Your data capturing system should provide some means of storing this information.
There is no general answer to this question. It is usually not possible for a single researcher to set up and maintain a compliant, secure data capturing system by him- of herself. As soon as (in)direct identification of human study subjects is possible, you should use a professional data capturing system. The system and its environment should preferably be NEN7510(2011) or ISO27001 certified. However, this is not always practically achievable yet. In the absence of such certification, you have to at least be able to demonstrate that the underlying essential goals of the NEN7510 (i.e., protection, accountability, privacy, documentation, risk assessment, quality management) are met. Ask your UMC's experts for lists of requirements.