The objective of this study is to propose a spatiotemporal data model (STDM) to systematically analyze the dynamic changes of market areas using the small business database provided by the Market Area Information System of Small Enterprise and Market Service and demonstrate the applicability of the model according to a series of analysis scenarios. In the literature review section, we reviewed studies related to indexes that summarize the changes in the small enterprise and market area and reflect their characteristics as well as studies on STDM and discussed the direction for application. In the methodology section, we presented methodologies to establish the STDM and relative diversity index (RDI) using the nationwide small business database. In the case study section, we established a nationwide STDM to monitor the changes in the RDI of the small business database based on a 1 km grid and demonstrated the applicability of the model by analyzing the RDI in the macroscale at the metropolitan/provincial level and in the 1 km grid-based mesoscale. Moreover, on the basis of the empirical results, we discussed that applying the grid-based STDM facilitates comparative analysis in terms of macroscopic, regional, and microscopic aspects by solving the modifiable areal unit problem (MAUP) that changes according to time, bringing convenience to the visualization analysis of spatiotemporal patterns, and establishing a grid-based RDI of small businesses with consistent spatial units.