• Normalization and dependency theory defined explicit schema decomposition and data integrity for relational databases, spanning multivalued dependencies and the fourth normal form, join theory, and domain/key normal forms with scheme equivalence analyses [3], [4], [11], [9], [15].

• Semantics-focused modeling seeks to capture deeper meaning in data beyond how it is stored, via SDM, semantic models, semantic web-oriented extensions, and view-based design to align database schemas with application contexts [2], [13], [18], [16], [12].

• Hardware-oriented database design studies dedicated machines and accelerators for relational workloads, detailing architecture concepts, database machine capabilities, and performance evaluations of relational processors [7], [14], [20].

• Data architecture and abstraction research compares generalized data systems, develops uniform treatment of objects, and investigates physical structure like record segmentation and blocking to improve storage and retrieval efficiency [8], [5], [10].