EER to Relational Translation Techniques
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- Опубликовано: 9 июл 2024
- Overview of 3 techniques for mapping an extended entity relationship (EER) model to a set of relational schema, the circumstances under which each technique applied, and the tradeoffs among the 3
thank you brian! saved my assignment on eer and the relation model,
Literally about to say the same thing. Just helped me finish my paper
Thank you so much!! I can only understand theis topics with you, my professor is really bad at explaining things. This will definitely help me throughout the semester.
Happy to help!
same as u
Thanks. That was quite helpful
Excellent Video. You just simplified some terribly written books. Thanx a lot !!!
you made me pass my exam
Thank you for the video. It was very helpful
Thank you so much Sir⭐⭐ amazing lesson , great representaion 👍
very, very clear!
well explained ^^ thank u man
Thank you so much for the video but I have a question. At the end of the video you were explaining overlap but there was no mapping in overlap.
Thank U Very Much Bro !! :D
This help me so muchh , thx bro
for the overlapping cases when for example
1) when an employee is admin , programmer and engineer
2) when an employee is programmer and engineer or any two among the three sub classes is there is any standard technique to represent the constraint in diagram.
thankx.
Hi in the video about the subclasses, wont they be applicable when there is covering constraint and not the disjoint??
Thank you sir❤
Most welcome
Great...ty!!!
What do the "U's" that you drew in represent?
The U indicates the direction of the specialization. The U is open towards the generalized entity. Given the possibility of multiple inheritance, it's possible otherwise to be confused about which entities are the generalized ones.
Can you please make a video on Union please?
programmers are engineers too ;)
With all in one, instead of binary classes, cant you represent it with a binary(max)? i.e:
0 -> {}
1 -> {Programmer}
01 -> {Engineer}
11 -> {Admin}
100 -> {Programmer, Engineer}
101 -> {Engineer, Admin}
110 -> {Admin, Programmer}
111 -> {Programmer, Engineer, Admin}
This would also make it easier to constrain again certain ones, i.e.
exclude: {0, 101, 111} etc.
Design the database for a programming support environment. In this environment programmers produce programs, which are written in given programming languages.
Each program is written by a given programmer, can call other programs, and can be used by given users. Users are recognized by their log-in names. Programmers are recognized by their log-in name and by their code. Programs have compound names that include the program's name, the extension and the programmer's code. Programs have a version number, a date and a short description; some programs interact with DBMSs. Each DBMS maintains stored data in the form of relations, with several attributes and one primary key. Each database is defined by a database administrator, who is a programmer specialized in data management. State clearly any assumptions you make.
Good morning, I seem to having issues creating the ERD with ISA
what did I do wrong?
Sorry, this looks to be homework. You should seek help via your instructor/institution
:(
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