Recent questions tagged relational-algebra

Consider the relations:$\mathrm{Users(username, name, email, password, address)}$and$\mathrm{FriendsWith(username, username2, sincewhen)}$.A friendship tuple indicates th...

Consider the relations:$\mathrm{STUDENT(name,regno,gpa,level,dept)}$$\mathrm{COURSE(cno,cname,dept)}$$\mathrm{TAKE(regno,cno)}$Using only the basic relational algebra ope...

Consider $R(a,b)$ and $S(c,d)$.Which relational algebra expression is equivalent to:SELECT a, d FROM R, S WHERE R.a 10 AND R.b = S.c;Use only the basic operators.$\pi_{a...

Let $R$ and $S$ be union-compatible relations.Which expression computes $R\cap S$ using only union and set difference?$(R\cup S)-((R-S)\cup(S-R))$ $(R\cup S)-(R-S)$ $(R-S...

Consider $\text{parts(pno, pname, price)}$.Which relational algebra expression returns exactly the names of all parts whose price is greater than $\$200$?$\pi_{\text{pnam...

Which of the following statements are correct?The HAVING CLAUSE is an optional clause which tells Oracle to group rows based on distinct values that exist for specified c...

Consider the given relations $X, Y$ and $Z$. The relation $X$ has three columns $P, Q$ and $R$. The relation $Y$ has three columns $P, Q$ and $S$. The relation $Z$ has tw...

I have a doubt in Relational algebra : Like we have the relations R(A B) and T(B C)and K(C D) here ABCD are attribute of relations then how can we perfom union operation...

Consider the following three relations:Employee (eid, eName), Comp(cid, cName), Own(eid, cid).Which of the following relational algebra expression return the set of eids ...

Consider a relation schema $\mathrm{R}=(\mathrm{U}, \mathrm{V}, \mathrm{W}, \mathrm{X}, \mathrm{Y}, \mathrm{Z})$, on which the following functional dependencies hold:$$\{...

Which of the following relations can not be decomposed in to BCNF with a lossless join and dependency-preserving decomposition?$\mathrm{R}(\mathrm{V}, \mathrm{W}, \mathrm...

Consider the following relations $\mathrm{X}(\mathrm{S}, \mathrm{Si}, \mathrm{C})$ and $\mathrm{Y}(\mathrm{S}, \mathrm{P}, \mathrm{D})$.$\mathrm{X}$ $\begin{array}{|c|c|c...

Consider the following relations $\mathrm{X}(\mathrm{S}, \mathrm{Si}, \mathrm{C})$ and $\mathrm{Y}(\mathrm{S}, \mathrm{P}, \mathrm{D})$.$\mathrm{X}$$\begin{array}{|c|c|c|...

Consider the following relations $\mathrm{X}(\mathrm{S}, \mathrm{Si}, \mathrm{C})$ and $\mathrm{Y}(\mathrm{S}, \mathrm{P}, \mathrm{D})$.$\mathrm{X}$$\begin{array}{|c|c|c|...

Consider the following relations $\mathrm{X}(\mathrm{S}, \mathrm{Si}, \mathrm{C})$ and $\mathrm{Y}(\mathrm{S}, \mathrm{P}, \mathrm{D})$.$\mathrm{X}$$\begin{array}{|c|c|c|...

C13. A directed graph can be represented by its edge-list and stored in a database table with attributes (source, target). For example, the following table stores the edg...