Tagged Questions
3
votes
1answer
173 views
Limiting database security
A number of texts signify that the most important aspects offered by a DBMS are availability, integrity and secrecy. As part of a homework assignment I have been tasked with mentioning attacks which ...
2
votes
1answer
327 views
Theta join explanation
Given the following question, I'd be glad if someone could help me.
Take the following relational schemes:
R(A, B , C)
S(D, E, F)
where A and D attributes are the primary keys.
Assume to ...
4
votes
2answers
528 views
1 <-> 0..1 relationship
I have "1 <-> 0..1 relationship". For example:
There is a set of users. Some users are customers.
Thus we have two tables: the table users and the table customers.
What is the best way to ...
4
votes
1answer
737 views
Calculate months between two dates
For a University course I've been given the following task
Suppose that we have an employee table like (first_name, last_name, salary, hire_date, ...). There is regulation which states that every ...
