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!
Multiple Assignment- SQL
SQL supports multiple assignment to local variables and also applies multiple assignment semantics in SET clauses of UPDATE statements, but does not support multiple assignment in connection with updates on table targets. Thus, SQL has no counterpart to the theory book's Example, simultaneously deleting from both COURSE and IS_ENROLLED_ON. If we assume that there must be at least one enrolment for each course, and that students can enroll only on existing courses, deferred constraint checking has to be used, as shown in Example here.
Example: Withdrawing course C3 and deleting any enrolments on C3
Assume the definition of IS_ENROLLED_ON includes
CONSTRAINT Course_must_exist_for_enrolment
FOREIGN KEY (CourseId) REFERENCES COURSE ON DELETE NO ACTION
and the definition of COURSE includes
CONSTRAINT Enrolment_must_exist_for_course
CHECK ( CourseId IN (SELECT CourseId FROM IS_ENROLLED_ON)
Multiple Assignment- SQL SQL supports multiple assignment to local variables and also applies multiple assignment semantics in SET clauses of UPDATE statements, but does not
Keyword and Parameter Description: label_name: This is an undeclared identifier which labels an executable statement or the PL/SQL block. You can use a GOTO statement to
#quesWrite a cursor to open an employee database and fetch the employee record whose age is greater than 45.tion..
Demonstrate your knowledge of PL/SQL programming by writing and thoroughly testing triggers and stored procedures associated with an e-commerce application that provides security l
How Transactions Guard Your Database The transaction is a sequence of SQL data manipulation statements which does a logical unit of work. The Oracle treats the sequence of SQL
Write a stored procedure that accepts the post code in which the customer resides as the input parameter. The procedure should then use an explicit cursor to display comprehensive
ORIGIN OF EARTH - BIG-BAN G HYPOTHESIS - Origin of life is linked to origin of earth. Cosmos, the Universe originated 10-20 billion years ago by Big Bang (thermonu
Using a join on 3 tables, select 5 columns and 10 rows from the 3 tables without the use of a Cartesian product Query: SELECT E.LAST_NAME, E.FIRST_NAME, S.BUILDING, S.BRAN
IS NULL Operator The IS NULL operator returns the Boolean value TRUE whenever its operand is null or FALSE if it is not null. The comparisons including the nulls always yield NU
Overview of control structures According to the structure theorem, any computer program can be written by using the basic control structures as shown in figure below. They can b
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