Explain weak and strong entity type, Database Management System

Assignment Help:

Explain weak and strong entity type ?

Weak and Strong entity type: An entity set which does not have a primary key is referred to as a weak entity set. The existence of a weak entity set depends on the existence of a strong entity set; it must associate to the strong set via a on-to-many relationship set. A discriminator of a weak entity set is the set of attributes that distinguishes between all the entities of a weak entity set. The primary key of a weak entity set is formed by the primary key of the strong entity set on that the weak entity set is existence depends, plus the weak entity set's discriminator.


Related Discussions:- Explain weak and strong entity type

Eliminate columns not dependent on key, Eliminate Columns Not Dependent On ...

Eliminate Columns Not Dependent On Key The Employee Relation satisfies - First normal form - As it has no repeating groups. Second normal form - As it do not have multi-a

Give the relational calculus queries of players in sql, An orchestra databa...

An orchestra database consists of the following relations: CONDUCTS (conductor, composition) REQUIRES (composition, Instrument) PLAYS (Player, Instrument) Give the relational

Storage of database on hard disks, Storage Of Database On Hard Disks At...

Storage Of Database On Hard Disks At this point, it is worthwhile to note the difference among the terms file Organisation and the access method. A file organisation shows to t

Create a subroutine, 1. Create a subroutine that does the remote blast on t...

1. Create a subroutine that does the remote blast on the file protein.fa. 2. Pass that returned files from the blast to another subroutine that parses the output and sends it to

Explain the terms data warehousing and data mining, Question: i) Explai...

Question: i) Explain the terms data warehousing and data mining. ii) Discuss the importance of the following security principles that a digital firm should amongst others, n

The transactions, The Transactions- A transaction is definite as the unit o...

The Transactions- A transaction is definite as the unit of work in a database system. Database systems that deal with a huge number of transactions are also termed as transaction p

Define deferred update technique of recovery, Discuss deferred update techn...

Discuss deferred update technique of recovery.  What are the advantages?  Ans:  The deferred update methods do not physically update the database on disk till after a transact

Explain the ansi -sparc schema architecture, (a) Differentiate between info...

(a) Differentiate between information and data . (b) List and briefly explain five potential benefits of the database approach compared to conventional file systems. (c) Diff

Explain the form of the create view command, We define a view in SQL throug...

We define a view in SQL through using the create view command. To describe a view, we must provide the view a name and must state the query in which computers the view. The form of

Serialisable schedules, Serialisable Schedules: If the processes of two tra...

Serialisable Schedules: If the processes of two transactions conflict with each other, how to verify that no concurrency related problems have happened? For this, serialisability t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd