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Abraham Silberschatz researches database management systems, operating systems and distributed computing, and coauthored the database text and teaching materials with Henry F. Korth and S. Sudarshan. His Yale profile identifies these research and teaching contributions.^[ref]

Their relational model slides make the distinction between a mathematical query expression and a safely evaluable database query explicit. For example, asking for all values not appearing in a finite table can range over an unlimited universe unless the query restricts its results appropriately. Restricting candidate values to those occurring in stored data makes the intended finite computation visible. This is one reason database theory specifies a query's semantics rather than relying on suggestive notation alone.^[ref]

Henry F. Korth studies database management systems, including database transactions and database query processing in parallel and distributed settings. His Lehigh profile records these research areas and work on database storage and aggregation systems.^[ref]

With Abraham Silberschatz and S. Sudarshan, he coauthored teaching material on the relational model. A relation is a set of tuples, so mathematical projection removes repeated result tuples; a query language or implementation that retains duplicates has different semantics unless duplicate removal is requested. For example, projecting the department column of two employee records from the same department gives one tuple under set semantics. Keeping this distinction explicit helps connect a declarative query to its actual result.^[ref]

S. Sudarshan researches database management systems, particularly database query optimization and the boundary between application code and database queries. His IIT Bombay research description explains work that rewrites repeated query invocations into batches or equivalent larger queries, combining program analysis with query planning.^[ref]

For example, an application can issue one query for each employee's department. Collecting the required identifiers and issuing a suitable combined query can reduce repeated communication, provided the rewrite preserves the original transaction and result semantics. Reducing the number of database calls is useful only if it preserves what the program computes. With Abraham Silberschatz and Henry F. Korth, Sudarshan also coauthored the database text and slides cited here.^[ref]