In a relational database, a table has 5 attributes and 1000 records. If a query returns 200 records after applying a condition, what is the selectivity of the query?

The first value in the output of a SQL query (given below) when run on a table having name “Table-1” is?

SQL Query: SELECT LastName FROM Table-1 WHERE State = "IN" ORDER BY FirstName

LastName	FirstName	StreetNumber	StreetName	City	State
Squires	Edwin	4589	Shamar Rd.	Upland	IN
Rothrock	Paul	91657	Carex Ave.	Upland	IN
Ramirez	Douglas	123	Fake St.	Springfield	IN
Peterson	Chris	4687	Windthrow Way	Kane	PA
Gibson	David	354	Bluestem St.	Carbondale	IL

GATE GE - 2025
Geographic Information System
Database Management Systems

View Solution

The table below is an attribute table about employee records. Which attribute can be used as a primary key?

Employee	Name	Designation	Department
(Emp_ID)	(Emp_Name)	(Emp_Desig)	(Emp_Dept)
100260	Prashant	Software Developer	Information Technology
100265	Dinesh	Junior Engineer	Embedded System
100252	Somya	HR Manager	Management
100271	Dinesh	Junior Engineer	Information Technology

GATE GE - 2025
Geographic Information System
Database Management Systems

View Solution

Consider the following database tables of a sports league. player (\( pid \), \( pname \), \( age \)) coach (\( cid \), \( cname \)) team (\( tid \), \( tname \), \( city \), \( cid \)) members (\( pid \), \( tid \)) An instance of the table and an SQL query are given.
Player table

coach table:

team table:

members table:

SQL query: \[ {SELECT MIN(P.age)} \] \[ {FROM player P} \] \[ {WHERE P.pid IN (} \] \[ { SELECT M.pid} \] \[ { FROM team T, coach C, members M} \] \[ { WHERE C.cname = 'Mark'} \] \[ { AND T.cid = C.cid} \] \[ { AND M.tid = T.tid)} \] The value returned by the given SQL query is _________. (Answer in integer)

View Solution

Consider a relational schema team(name, city, owner), with functional dependencies \( \{ {name} \rightarrow {city}, {name} \rightarrow {owner} \} \). The relation team is decomposed into two relations, \( t_1({name}, {city}) \) and \( t_2({name}, {owner}) \). Which of the following statement(s) is/are TRUE?

View Solution

A schedule of three database transactions \(T_1\), \(T_2\), and \(T_3\) is shown. \(R_i(A)\) and \(W_i(A)\) denote read and write of data item A by transaction \(T_i\), \(i = 1, 2, 3\). The transaction \(T_1\) aborts at the end. Which other transaction(s) will be required to be rolled back?

View Solution

In a relational database, a table has 5 attributes and 1000 records. If a query returns 200 records after applying a condition, what is the selectivity of the query?

Show Hint

The Correct Option is A

Solution and Explanation

Top Questions on Database Management Systems

Questions Asked in AP PGECET exam