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!
During the deletion of a tuple two cases can happen:
Deletion of tuple in relation having the foreign key: In this type of case simply delete the desired tuple. For example, in ASSIGNMENT relation we can simply delete the first tuple.
Deletion of the target of a foreign key reference: For instance, an attempt to delete an employee tuple in EMPLOYEE relation whose EMPID is 101. This employee shown not only in the EMPLOYEE but also in the ASSIGNMENT relation. Can these tuple be deleted? If we delete the tuple in EMPLOYEE relation then two unequalled tuples are left in the ASSIGNMENT relation, therefore causing violation of referential integrity constraint. Therefore, the following two choices be for such deletion:
RESTRICT - The delete operation is "restricted" to only the situation where there are no such matching tuples. For instance, we can delete the EMPLOYEE record of EMPID 103 as there is no matching tuple in ASSIGNMENT but not the record of EMPID 101.
CASCADE - The delete operation "cascades" to delete also those matching tuple. For instance, if the delete mode is CASCADE then deleting employee having
EMPID as 101 from EMPLOYEE relation will also make deletion of 2 more tuples from ASSIGNMENT relation.
What is DML compiler? DML Compiler: Translates DML statements in a query language within low level instructions understandable through the query evaluation engine. Attempts to
You are required to write a report which evaluates two of the following issues in relation to your case study database: a. Security issues b. Performance issues c. Backup
Data independence seems that "the application is independent of the access strategy and storage structure of data". In other words, the ability to change the schema definition in o
What is object containment? References among objects can be used to model dissimilar real-world concepts.
What is the difference between serial and sequential files? How searching is applied on both? Ans: A serial file is one where the records have been stored in the order where
With the help of a diagram defines the typical element modules of a DBMS? The functional elements of a database system can be widely divided into: 1) Storage manager and 2) q
Lossless-Join Decomposition Let us show an intuitive decomposition of a relation. We require a better basis for deciding decompositions since intuition may not always be r
(a) Why did SAP introduce the extended star schema?
What is known as heap file organization? In the heap file organization, any record can be placed anywhere in the file where there is space for the record. There is no ordering
The traffic data mgmt. systems infrastructure plan describes the software, hardware, data network, and other elements that will support the TDMS. The infrastructure plan is based o
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