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 the basic operations of the relational algebra?
Ans: Basic operators of relational algebra are:
1. Union (∪) - Selects tuples which are in either P or Q or in both of them. The duplicate tuples are removed.
R = P ∪ Q
2. Difference or Minus (-) - eliminates common tuples from the first relation.
R = P - Q
3. Cartesian Product or Cross Product (×) - The cartesian product of two relations is the concatenation of tuples that are belonging to the two relations and containing all possible combination of the tuples.
R = P× Q
4. Projection (π) - The projection of a relation is illustrated as a projection of all its tuples over some set of attributes that is it yields a vertical subset of the relation. The relation's projection T on the attribute A is presented by T [A] or πA(T),.
5. Selection (σ) - Selects just some of the tuples, those satisfy specified criteria, from the relation. It yields a horizontal subset of a following relation.
R = σB(P)
What are the various states through which a transaction passes through in its lifetime? Briefly discuss all the events that causes transition from one state to another. Ans:
What is recursive closure? Why is it not possible to describe this operation in relational algebra? Recursive closure is applied to recursive relationship. An instance of rec
What do you mean by atomicity and aggregation? Atomicity : Either all actions are carried out or none are. Users should not have to worry about the effect of incomplete trans
Project Description: This is a Customer Management project. Customer data is presented in a text file. The program can load this text data into its database columns. The data ma
Control Files : The redo and control files logs support the rest of the architecture. Every database must have at least one control file, although you have more than one to guard
Define the terms 1) physical schema 2) logical schema. Physical schema: The physical schema explains the database design at the physical level, which is the lowest lev
Project Description: I would like to get a database of a website which has clients email name and phone number. If you are able to get information from a website, by entering
Define Database layer? The database layer defines the data formats used in the database.
Explain the term- Query. Queries are used to repossess and show specific records in a table. They can also be used to show specific fields of specific records, which meet the co
What are the different kinds of database end users? Discuss the major activities of each? End-Users - End-users are the people whose jobs need access to the database for que
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