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 nested relations?
Nested relations
The assumption of INF is a natural one in the bank examples we have considered.
However, not all applications are best modelled by INF relations.
The nested relational model is an extension of the relational model in which domains might be either atomic or relation valued.
We illustrate nested relations by an example from a library. Assume we store for every book the following in formations
Book title
Set of authors
Publishers
Set of keywords
We can see that if we describe a relation for the preceding information, several domains will be monatomic
Authors
Keywords
Complex types
Collection and large object types
Create table books(
...
Keyword-set setoff(varchar(20))
)
Structure types
Creation of values of complex types
What is Relational calculus? Relational calculus is a Non- Procedural language.
What is a candidate key? Minimal super keys are known as candidate keys.
Record based Logical Models: Use records as the key data representation components Examples: Relational Model: It shows data as well as relationship between data in the form
For every n-ary relationship type R where n>2, we make a new table S to represent R. We contain as foreign key attributes in s the primary keys of the relations that show the parti
Benefits and Limitations od Data Models?
Example -GRANT CREATE SESSION TO MCA12; (This command gives system level permission on creating a session - not portable) GRANT SELECT ON EMP TO MCA12; (Object level permi
Let us first describe the term relationships. What Are Relationships? A relationship can be defined as: A set of associations or connection, or A rule for communic
Project Description: Need Point of Sale software for pizza restaurant. Delivery and take out service, client's database, inventory control, order history, last order, order from
A use case diagram giving a pictorial overview of user requirements and brief use case descriptions. As the case study contains only an outline of a business scenario, you will als
External failure : A failure can also result because of an external cause, such as earthquakes, fire, floods, etc. The database must be duly backed up to avoid troubles occurring d
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