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)
Delimiters A delimiter is a simple or compound symbol which has a special meaning to PL/SQL. For example, you use delimiters to symbolize an arithmetic operation like additio
Closing a Cursor Variable The CLOSE statement disables the cursor variable. After that, the related result set is undefined. The syntax for the same is as shown below: CLOS
Write a cursor to open an employee database and fetch the employee record whose age is greater than 45
Parameter and Keyword Description: record_type_name: This identifies the user-defined type specifier that is used in the subsequent declarations of the records. NOT N
Advantages of Wrapping The PL/SQL Wrapper convert the PL/SQL source code into a transitional form of the object code. By hiding the application internals, the Wrapper secure
1. Create a procedure called TAX_COST_SP to accomplish the tax calculation task. Keep in mind that the state and subtotal values are inputs into the procedure and the procedure is
%TYPE Attribute The %TYPE attribute gives the datatype of a record, field, nested table, database column, or the variable. You can use the %TYPE attribute as the datatype speci
set serveroutput on declare a number(5); b number(5); c number(5); begin a:=&a; b:=&b; c:=a/b; dbms_output.put_line(c); exception when zero_divide then d
CHECK Constraints in SQL A CHECK constraint is a table constraint defined using the key word CHECK, as already illustrated in several examples in this chapter. In particular,
Parameter and Keyword Description: table_reference: This keyword identifies the table or view that should be accessible when you execute the UPDATE statement, and for wh
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