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.
For each 1: n relationship type R involving two entities E1 and E2, we recognize the entity type (say E1) at the n-side of the relationship type R and contain primary key of the en
Describe sequential file organization. Explain the rules for (i) Inserting a new record. (ii) Deleting an existing record. Ans:A sequential f
Define blocks? The database system resides eternally on non-volatile storage, and is into fixed-length storage units known as blocks.
Ask q“A database will be made to store information about patients in a hospital. On arrival, each patient’s personal details (name, address, and telephone number) are recorded wher
10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the
Example: //REVOKE ALL ON EMP FROM MCA12; (All permissions will be cancelled) You can also cancel only some of the permissions. Drop: A user-
What are domain constraints? A domain is a set of values that might be assigned to an attribute .all values that appear in a column of a relation must be taken fro
what is view?explain
Security: In a centralised system, access to the data can be simply controlled. Though, in a distributed DBMS not only does access to replicated data have to be controlled in many
Oracle Fusion Middleware: Key Skills: Consulting,Architect, Oracle Fusion Middleware,ECM, UCM, Stellent,Identity Management, SOA Suites, BPEL, ESB,OAM,OIM,J2ee, Java, Livelink
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd