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!
List two restrictions that are applied on the modification (updation, insertion or deletion) of base tables through view.
Ans: The two restrictions are:
1. If a view does not consist of primary key and/or at least one of the attributes along with the NOT NULL constraint which do not have default values specified, is not updatable. This restriction is needed because if we are inserting any row in the view than all attributes not included in view of the base relation are will be denoted by the NULLs if any default value is not specified. In this type of case, if any attribute is set as NOT NULL or primary key, then it should not be NULL, and the insertion will be violating the constraints.
2. If a view defined by using grouping and/or aggregate functions, is not updatable. This restriction is also needed because, if we want to modify the base relation by view then we are not in the position to identify that tuple(s) will be modified in the group in what way.
What is a guard condition? Explain it with a suitable example. The guard-condition is a Boolean expression written with respect to parameters of triggering event and attributes
Describe sequential file organization. Explain the rules for (i) Inserting a new record. (ii) Deleting an existing record. Ans:A sequential f
What is a state chart diagram? State diagrams (State Chart Diagram) explain all possible states that a particular object can get into, and how object's state changes as result
What do you mean by persistence? How you will make your data persistent? Persistent data is the data, which has a longer lifetime than program which has created it. Enabling th
What are the features of embedded SQL? Explain. Embedded SQL - SQL could be implemented within two ways. It can be used interactively or embedded in a host language or throu
A student entity type has the following attributes,name..
1. Will you advise that your organization uses open source software and why? 2. Why is it important for business managers to have a basic understanding of the software development
Define multivalued dependency. What do understand by trivial multivalued dependency? Ans: A multivalued dependency is a full constraint among two sets of attributes in a rela
Describe how you can simplify Operations. To simplify operation, one should use inheritance, where possible to use, to reduce the quantity of distinct operations. Introduce new
The primary key is selected from the
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