Let S be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following ER diagrams CORRECTLY represents S?
In a B+ tree, the requirement of at least half-full (50%) node occupancy is relaxed for which one of the following cases?
Which of the following statements about a relation R in first normal form (1NF) is/are TRUE?
Which one of the options given below refers to the degree (or arity) of a relation in relational database systems?
In a relational data model, which one of the following statements is TRUE?
Consider a simple undirected graph of 10 vertices. If the graph is disconnected, then the maximum number of edges it can have is ____________.
Consider a relation R(A, B, C, D, E) with the following three functionaldependencies. 𝐴𝐵 𝐶; 𝐵𝐶 𝐷; 𝐶 𝐸; The number of superkeys in the relation R is _____________.
Let Ri(z) and Wi(z)denote read and write operations on a data element z by a transaction Ti, respectively. Consider the schedule S with four transactions. S: R4(x) R2(x) R3(x) R1(y) W1(y) W2(x) W3(y) R4(y) Which one of the following serial schedules is conflict equivalent to S?
Consider a relational database containing the following schemas. The primary key of each table is indicated by underlining the constituent fields. SELECT s.sno, s.snameFROM Suppliers s, Catalogue cWHERE s.sno=c.sno AND cost (SELECT AVG (cost) FROM Catalogue WHERE pno = 'P4' GROUP BY pno); The number of rows returned by the above SQL query is
Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram?
Consider the following five disk five disk access requests of the form (request id, cylinder number) that are present in the disk scheduler queue at a given time. (P,155), (Q,85), (R,110), (S,30), (T,115) Assume the head is positioned at cylinder 100. The scheduler follows the Shortest Seek Time First scheduling to service the requests. Which one of the following statements is FALSE?
Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE??
Consider a schedule of transactions T1 and T2: Here, RX stands for "Read(X)" and WX stands for "Write(X)". Which one of the following schedules is conflict equivalent to the above schedule?
Consider a database implemented using B+ tree for file indexing and installed on a disk drive with block size of 4 KB. The size of search key is 12 bytes and the size of tree/disk pointer is 8 bytes. Assume that the database has one million records. Also assume that no node of the B+ tree and no records are present initially in main memory. Consider that each record fits into one disk block. The minimum number of disk accesses required to retrieve any record in the database is _______.