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
Complete replication: It implies maintaining of a whole copy of the database at every site. Thus, the reliability & availability and performance for query response are maximized.
What disadvantage of ODBC does OLE DB overcome? By breaking the features and the methods of a DBMS into COM objects, OLE DB characteristic overcomes a main disadvantage of ODBC
Database Manager It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as
Define Timestamp ordering Ans In timestamp-based method, a serial order is made among the concurrent transaction by assigning to every transaction a unique nondecreasing number
Compare the Nested-loop join and block-nested loop join Ans: Nested loop join - It is costly as worst case cost, no. of block accesses needed is n r * b s + b r where b
What is Relational Algebra? Relational algebra is a Procedural query Language?
what is object-identity
online eductional management system ke diagram
First Normal Form and second normal form First Normal Form (1NF) A relation is said to be in 1NF if it having no non-atomic values and each row can give a unique combinat
An entity type usually has an attribute whose values are distinct for every individual entity in the collection. Such an attribute is known as a key attribute and its values can be
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