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.
Rearrange Classes and Operations Sometimes, the similar operation is defined across different classes and can easily be inherited from a familiar ancestor, but more often oper
#ques Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a p
What is primary Key Explain? Primary Key - Primary key is one of the candidate keys. It should be selected such in which its attribute values are never, or very rarely, chang
What is Information System?
What is called block-level striping? Block level striping stripes blocks across many disks. It treats the array of disks as a large disk, and provides blocks logical numbers
Find the names of all Albums that have more than 30 tracks. Result: (name: varchar(255))
Question: In a multi-user database environment, locking mechanisms can be used to solve the three basic problems of concurrency. On the other hand, however, locking may also le
Q. Explain the terms key constraints participation constraints and mapping caradinalities in ER model. Participation Constraints : The participation of an entity set E i
Describe Dynamic Model. The dynamic model specifies allowable sequences of changes to the objects from an object model. It contains event trace diagrams describing scenarios. A
draw er diagram using entities crop,employee,department,plot,cultivation plan,machinery,seed,fertilizer
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