EQUIVALENCE OF FUNCTIONAL DEPENDENCIES

-
You will be given a relation (R) with different functional dependency sets X,Y of that relation , you need to check whether one functional dependency is a subset of other (X⊇Y/ Y"⊇"X ) or both are equal (X=Y). 

Consider X and Y are two FD sets for a relation R , 

1)If all FDs of X can be determined from FDs that are present in Y, we can conclude that Y  ⊇  X    or X⊆ Y    (Y covers X)  . 

2)If all FDs of Y can be determined from FDs that are present in X, we can conclude       X ⊇ Y  or Y⊆ X (X covers Y).


3)If 1 and 2 are satisfied then ,we can say X=Y  or X and Y are equivalent .

Comments

Post a Comment

Popular posts from this blog

COMPUTER ORGANISATION & ARCHITECTURE TUTORIAL 1

-
Image
We can start learning basics of Computer Organisation & Architecture  .  Understand the difference between computer architecture & organisation first . BASIC OPERATIONAL CONCEPTS  We can discuss about various operations used for transferring and manipulating data BUS STRUCTURE We can consider definition of BUS also about way of transferring data through Bus . MEMORY LOCATIONS & ADDRESSING Understand the basics of System Memory ,way of storing data in memory.  W can discuss here about memory addresses and about Byte addressable memory .At the end we will get the idea about memory size specification and how to calculate the address of memory bytes . INSTRUCTION EXECUTION &STRAIGHT LINE SEQUENCING Understand what an instruction is ,then learn about how to complete the execution of a program which is present in main memory of the system by executing set of instructions one after another . Here consider , two situations of instruction executi...
Read more

MODULE 4- BASIC PERIPHERALS AND THEIR INTERFACING WITH 8086

-
MEMORY INTERFACING            Communication between processor and memory is known as interfacing with memory (RAM or ROM) memory access possible by using Memory Read signals and Memory write signals. System is associated with different memory chips ,so processor need to properly fix one among them for performing memory access operations. So need a chip selection signal for selecting a memory chip properly . All these signals are generated by a device for supporting memory access operation is known as memory interfacing unit .
Read more