Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Explain algorithm of ER To Relational Mapping ?
ER-to-Relational Mapping Algorithm:
1) Step 1: Mapping of regular entity types: For each strong entity type E, form a relation T which involves all the easy attributes of a composite attribute.
2) Step2: Mapping of weak entity types: For each weak entity type W along with owner entity type E, create relation R and involve all easy attributes (or simple components of composite attributes) of W as attributed of R. In addition, involves as foreign key attributes of R, the primary key attribute (s) of relation(s) which correspond to the owner(s) and the partial key of the weak entity type W, if any.
3) Mapping of relationship types: form a relation R, for relationship along with primary keys of participating relations A and B as foreign keys in R. Further to this, any attributes of relationship become an attribute of R also.
4) Mapping of multivalued attributes: For every multilvalued attribute A, form a new relation R. This relation R will involve an attribute corresponding to A, plus primary key attribute K-as a foreign key in R-of the relation which represents the entity category or relationship type that has A as an attribute.
Sub query in the UPDATE command : Example : //Double the commission for employees, who have got at least 2 increments. UPDATE EMP SET COMM = COMM * 2 WHERE
What is Nested Trigger? A trigger can also having INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause ano
Question 1 Describe the following- Clustering Indexing Question 2 Explain the following with suitable real time examples- Implementation of Integrity rules
Illustrate the State model for the ATM class let us take state model for the ATM class given below in Figure showing state model of the ATM class and the pseudo code derived fr
Draw entity relationship diagram for the following scenario. A university has many departments whereas each department belongs to that particular uni. That uni has also many bui
it can be possible to create any table without primary key
Describe Participation Constraints? Participation Constraints - The participation constraint exacts whether the existence of an entity depends on its being related to another
read-set(T) : Each data items that are read by a transaction T Timestamps : for all transaction T, the start-time and the end time are reserved for all the three phases.
random file orgnization
Sequential File Organisation The most necessary way to organise the collection of records in a file is to use sequential Organisation. Records of the file are stored in series
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd