After modeling the entities with their attributes and defining the relationships between attributes, we have to normalize the model (normalization of data is a process of removing data anomalies and adjusting relations to have several desirable characteristics).
Testing needs to be done to identify and remove errors in the design and implementation of the database, structure and constraints e.t.c. There are two main tasks involved; validation and verification.
Validation checks whether the right solution has been developed to meet the specific requirements while verification checks whether the database has been implemented correctly according to the functional requirements set.
After the database becomes functional the maintenance phase comes into play to ensure smooth working, identification and resolution of problems and further improvements if necessary are made in this stage. (Sumathi & Esakkirajan, 2007)
As the name suggests the above mentioned process is not linear rather it is cyclic. This means that movement can take place to and fro from any stage of the cycle. Consider an example where the developers forget to include an important system requirement, they would then have to move (cycle) back to the requirements gathering phase and then make changes in the design and implementation stages as well for the adjustment. Also the end phase of maintenance does not actually mean a full stop in the relational database life cycle since the output of the maintenance phase such as identification of a problem or new enhancements require going back to the drawing board i.e. the requirements analysis and design phase. As one can clearly see the most consistently recurring phase in the event of any changes being made in the database is the design phase but it is to be kept in mind that changes in design require extensive efforts to resolve. This leads to my opinion of the requirements phase being the most important of all amongst the others. If requirements analysis is done properly and thoroughly then there would be no need for major design changes afterwards and most of the problems discussed above will easily be avoided. So, in my opinion this is one phase in which most time and efforts should be invested as they lead to greater time,