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)
query to Find the account numbers of all customers whose balance is more than 10,000 $
Need for Dynamic SQL: You need dynamic SQL in the situations as follows: 1) You would like to execute a SQL data definition statement (like CREATE), a data control statemen
Pass the nulls to a dynamic SQL: Passing Nulls: Assume that you want to pass the nulls to a dynamic SQL statement. For illustration, you may write the EXECUTE IMMEDIATE
Recursive Subprograms The recursive subprogram is the one that calls itself. Think of a recursive call as a call to a few other subprograms that does the similar task as your
SQLs counterpart of the key words: The text from the opening parenthesis to the end of the fourth line specifies the declared type of the table, meaning that every table ever
(a) What are decision support systems, and what role do they play in the business environment? (b) Data warehousing is defined as "a subject-oriented, integrated, non-volatile c
Main features of PL/SQL A good way to get familiar with PL/SQL is to look at a sample program. The below program processes an order for tennis rackets. At first, it declares a
Adding Table Constraints ALTER TABLE ENROLMENT ADD CONSTRAINT NameNotNull CHECK (Name IS NOT NULL) ; ALTER TABLE ENROLMENT ADD CONSTRAINT PK_StudentId_CourseId PRIM
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
Map and Order Methods: The values of the scalar datatype like CHAR or REAL have a predefined order that allows them to be compared. While, the instances of an object type has
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