Database theory encapsulates a broad range of topics related to the study and research of the theoretical realm of

database
In computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softw ...

s and database management system
In computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softw ...

s.
Theoretical aspects of data management include, among other areas, the foundations of query languages, computational complexity and expressive power of queries, finite model theoryFinite model theory (FMT) is a subarea of model theory
In mathematics
Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathematical structure, structure (algebra), space (geometry), and ...

, database designDatabase design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model.Teorey, T. ...

theory, dependency theory
Dependency theory is of the notion that resources flow from a "periphery
Periphery or Peripheral may refer to:
*Periphery (band), American progressive metal band
*Periphery (album), ''Periphery'' (album), released in 2010 by Periphery
*Periphery ...

, foundations of concurrency control
In information technology and computer science
Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application.
Computer sci ...

and database recovery
A database is an organized collection of Data (computing), data, generally stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal #Design and modeling, design and modeling ...

, deductive databases, temporal database, temporal and spatial databases, real-time databases, managing uncertain data and probabilistic databases, and Web data.
Most research work has traditionally been based on the relational model, since this model is usually considered the simplest and most foundational model of interest. Corresponding results for other data models, such as object-oriented or semi-structured models, or, more recently, graph data models and XML, are often derivable from those for the relational model.
A central focus of database theory is on understanding the complexity and power of query languages and their connection to logic. Starting from relational algebra and first-order logic (which are equivalent by Codd's theorem) and the insight that important queries such as graph reachability are not expressible in this language, more powerful language based on logic programming and fixpoint logic such as datalog were studied. Another focus was on the foundations of query optimization and data integration. Here most work studied conjunctive query, conjunctive queries, which admit query optimization even under constraints using the chase (algorithm), chase algorithm.
The main research conferences in the area are the ACM Symposium on Principles of Database Systems (PODS) and the International Conference on Database Theory (ICDT).
See also

*Conjunctive query *Expressive power (computer science), Expressive powerReferences

General references

* * David Maier, The Theory of Relational Databases. Copyright 1983 David Maier. Available at http://web.cecs.pdx.edu/~maier/TheoryBook/TRD.htmlExternal links

* {{Database Database theory, Database management systems, Theory