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!
Define entity integrity and referential integrity. How does SQL allow specification of these?
Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values.
Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.
In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.
These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:
Explain the use of constraints in functional model with suitable example. A constraint shows relationship between two objects at same time, or among various values of the sam
What is a relationship called when it is maintained between two entities? A relationship is called Binary relationship when it is maintained between two entities.
One-to-one relationship: For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participatio
Describe Parameteric end users? Parametric end users might be given update access, but are commonly not permitted to change the structure of data.
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
Synonyms and Indexes Some of the essential properties of indexes are: An Index is a schema Object Indexes can be formed explicitly or automatically Indexes are m
Write short notes on relational constraints? Relational Constraints are: 1. NOT NULL 2. Unique 3. Primary key 4. Foreign key 5. Table check
How can we Classify the operations on classes This step fundamentally means all three models functional, object and dynamic (studied in last section) must be combined so that
What is Relational Algebra? Relational algebra is a Procedural query Language?
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
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