Sort 6 Discussions, By:
Please Login in order to post a comment
In which language these queries have written..?
1) Student ⊳⊲(Number=ID) Teaching Assistants
2) π(Name, Number)(Student)
These aren't queries, these are notations to represent database operations. Queries are written according to these equations.
But lets be real, nobody cares about these. :P
these are symbols from relational algebra
i dont understand the ques-7
please can u elaborate
Does it mean that ⊳⊲ means inner join? I put 2 as answer and it is correct.
please comment that query and please explain that
We Join the tables using two columns Number and ID.The Join would bring the values which are present in both the tables where the values in Number column matches with the value in ID column.In our case,we have two matching values(3412 and 2341) and so the final output would contain 2 rows with all the columns from both these tables.Since they have asked the count the answer is 2.
but the answer is 2
First thing is what is the meaning of Num? There is no attribute like this in the second table. However, I assumed that it meant ID attribute. If it is, then the answer should be 2 as there are two field matched(3412,2341). But the Accepted answer is 1. Am I missing something?
Edited as appropriate -- thanks for pointing out
Confusing for me.
No more comments