Dependency Preserving Decomposition

-

Dependency Preserving Decomposition 

If we decompose a relation R into relations R1 and R2, All dependencies of R either must be a part of R1 or R2 or must be derivable from  FD’s of R1 and R2.  

Relation R is decomposed in to R1 and R2 with FDs F1 and F2 respectively  ,  if the decomposition is dependency preserving then

F1 U F2 =F


                                             and so           ( F1 U F2 ) + =F+



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 execution ,sequential execution and 
Read more