Database Theory
Database Theory
Course with SWS 4/2/0 (lecture/exercise/practical) in SS 2025
Lecturer
Tutor
SWS
- 4/2/0
Modules
Examination method
- Oral exam
Lecture series
Databases are a key technology in computer science that brings together fascinating theoretical topics and highly relevant practical applications. The goal of this lecture is to give an extended introduction to this interesting field, with a special focus on database query languages, their expressive power, and computational complexity. The lecture will introduce the relational data model, and then discuss theoretical and practical aspects of a variety of query languages:
- first-order logic as a query language and the relational algebra
- conjunctive queries and their unions
- navigational queries: path queries
- Datalog and its relatives
- query answering under database dependencies
The lecture focuses on core principles that apply to many types of databases alike (relational, graph-based, semantic web). Some important query answering algorithms are presented, too, but otherwise, the details of database implementation and administration are not covered.
Prerequisites
Undergraduate-level knowledge of predicate logic, regular languages, and algorithmic and computational complexity is required. The lecture will connect with other topics in the Computer Science and Computational Logic curriculum, such as relational databases, logic programming, and Semantic Web technologies – familiarity with these topics is not required to follow the lecture.
Schedule and Location
- The weekly lecture sessions will take place on Mondays from 09:20 to 10:50 in room APB E007 and Tuesdays from 09:20 to 10:50 in room APB E005.
- The weekly exercise session will take place on Tuesdays from 14:50 to 16:20 in room APB E005.
- The first exercise session will be on Tuesday, 2025-04-15.
Examinations
Dates for oral exams will be announced in due time. As usual, you should book a date with our secretary after you have officially enrolled in your respective examination office/system.
Legacy
This course has first been taught at TU Dresden by Prof. Dr. Markus Krötzsch in the form of the 2015 lecture Foundations of Databases and Query Languages, and later in the Database Theory lecture series. The plan for this year's course will be somewhat similar.
The structure of some of the lectures of this course is inspired by the course Theory of Data and Knowledge Bases in the version given by Georg Gottlob and Thomas Lukasiewicz at the University of Oxford.The main reference textbook for the lecture is:
- Serge Abiteboul, Richard Hull, Victor Vianu: Foundations of Databases. Addison-Wesley. 1994.
- The book is available for free from its webpage, but there are also copies in the library.
Further texts might be consulted for background information and additional details:
- Michael Sipser: Introduction to the Theory of Computation. 2005
- Accessible introduction to complexity theory that covers all topics of computational complexity that the lecture touches upon.
- Evgeny Dantsin, Thomas Eiter, Georg Gottlob, Andrei Voronkov: Complexity and expressive power of logic programming. ACM Computing Surveys, 33:3, pp 374-425, 2001.
- Covers all Datalog complexity results mentioned in the lecture. Available at http://dx.doi.org/10.1145/502807.502810 (may require access from within a university network)
- additional references may be added in the course of the lecture
Subscribe to events of this course (icalendar)
| Lecture | Introduction/Relational Data Model | DS2, April 7, 2025 in APB E007 | File 1, File 2 |
| Lecture | First-Order Queries | DS2, April 8, 2025 in APB E005 | File 1, File 2 |
| Lecture | Complexity of Query Answering | DS2, April 14, 2025 in APB E007 | File 1, File 2 |
| Lecture | Query Complexity of FO Query Answering | DS2, April 15, 2025 in APB E005 | File 1, File 2 |
| Exercise | 1. Relational Algebra | DS5, April 15, 2025 in APB E005 | File 1, File 2 |
| No session | No Lecture: Easter Monday | DS2, April 21, 2025 in APB E007 | |
| Lecture | Data Complexity of FO Query Answering | DS2, April 22, 2025 in APB E005 | File 1, File 2 |
| Exercise | 2. First-Order Queries | DS5, April 22, 2025 in APB E005 | File 1, File 2 |
| Lecture | Conjunctive Queries | DS2, April 28, 2025 in APB E007 | File 1, File 2 |
| Lecture | Tree-Like Conjunctive Queries (1) | DS2, April 29, 2025 in APB E005 | File 1, File 2 |
| Exercise | 3. Complexity of First-Order Queries | DS5, April 29, 2025 in APB E005 | File 1, File 2 |
| Lecture | Tree-Like Conjunctive Queries (2) | DS2, May 5, 2025 in APB E007 | File 1, File 2 |
| Lecture | Query Optimisation | DS2, May 6, 2025 in APB E005 | File 1, File 2 |
| Exercise | 4. Conjunctive Queries, CSP, and Hypergraphs | DS5, May 6, 2025 in APB E005 | File 1, File 2 |
| Lecture | Conjunctive Query Optimisation | DS2, May 12, 2025 in APB E007 | File 1, File 2 |
| Lecture | Query Expressiveness | DS2, May 13, 2025 in APB E005 | File 1, File 2 |
| Exercise | 5. Tree Width and Hypertree Width | DS5, May 13, 2025 in APB E005 | File 1, File 2 |
| Lecture | Query Expressiveness (continued) | DS2, May 19, 2025 in APB E007 | |
| Lecture | Query Expressiveness (continued) | DS2, May 20, 2025 in APB E005 | |
| Exercise | 6. Trakhtenbrot's Theorem | DS5, May 20, 2025 in APB E005 | File 1, File 2 |
| Lecture | Introduction to Datalog / Datalog Complexity | DS2, May 26, 2025 in APB E007 | |
| Lecture | Datalog Expressivity and Containment | DS2, May 27, 2025 in APB E005 | |
| Exercise | 7. FO Query Expressivity | DS5, May 27, 2025 in APB E005 | File |
| Lecture | Datalog Expressivity and Containment (continued) | DS2, June 2, 2025 in APB E007 | |
| Lecture | Datalog Evaluation (1) | DS2, June 3, 2025 in APB E005 | |
| Exercise | 8. Datalog | DS5, June 3, 2025 in APB E005 | |
| No session | No Lecture: Pentecost | DS2, June 9, 2025 in APB E007 | |
| No session | No Lecture: Pentecost | DS2, June 10, 2025 in APB E005 | |
| No session | No Exercise: Pentecost | DS5, June 10, 2025 in APB E005 | |
| Lecture | Datalog Evalution (2) / Graph Databases | DS2, June 16, 2025 in APB E007 | |
| Lecture | Path Queries | DS2, June 17, 2025 in APB E005 | |
| Exercise | 9. Semi-Positive Datalog | DS5, June 17, 2025 in APB E005 | |
| Lecture | Dependencies | DS2, June 23, 2025 in APB E007 | |
| Lecture | The Chase | DS2, June 24, 2025 in APB E005 | |
| Exercise | 10. Datalog Evaluation | DS5, June 24, 2025 in APB E005 | |
| Lecture | The Chase (continued; termination and acyclicity) | DS2, June 30, 2025 in APB E007 | |
| Lecture | Query Answering Beyond Acyclic TGDs | DS2, July 1, 2025 in APB E005 | |
| Exercise | 11. Graph Databases and Path Queries | DS5, July 1, 2025 in APB E005 | |
| Lecture | TBA | DS2, July 7, 2025 in APB E007 | |
| Lecture | TBA | DS2, July 8, 2025 in APB E005 | |
| Exercise | 12. Dependencies | DS5, July 8, 2025 in APB E005 | |
| Lecture | Outlook/Summary | DS2, July 14, 2025 in APB E007 | |
| Consultation | Consultation (time for your questions) | DS2, July 15, 2025 in APB E005 |
Calendar
