Lecture 5: Relational Algebra

Title slideTuesday’s lecture presented a mathematical language for slicing and dicing the structured tables of the relational model: selection, projection, renaming; union, intersection, difference; cross product, join, equijoin and natural join. A key feature of this relational algebra is that just six of these operations are enough to capture an extremely wide range of queries and transformations of data. Database implementors work hard to build highly efficient engines to carry out these operations, which can then support many different kinds of user application.

Links: Slides for Lecture 5; Video of Lecture 5

References

Tutorials are now under way, and these are a selection of sources for help and support in your study.

Pictures of all course tutors Course Tutors
Please prepare for your tutorials: attempt the exercises, bring along your work, and where you are stuck spend time think in advance what you will ask your tutor to help with.

Link: Course tutors

Screenshot of InfBASE home page InfBASE
Drop-in centre staffed by tutors: AT 5.02 at 1600—1800 every Monday, Tuesday, Thursday and Friday.

Link: InfBASE home page

Screenshot of computing help pages Computing Help
Use our custom help pages for DICE and Informatics computing.

Links: Informatics computing help; Computing support form

Screenshot of Inf1-DA on Piazza Piazza
Questions and answers, with contributions from students and teaching staff.

Link: Inf1-DA on Piazza