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!
Example of Using Aggregation on Nested Tables
Example: How many students sat each exam
WITH C_ER AS (SELECT CourseId, CAST (TABLE (SELECT DISTINCT StudentId, Mark FROM EXAM_MARK AS EM WHERE EM.CourseId = C.CourseId) AS ROW ( StudentId SID, Mark INTEGER ) MULTISET) AS ExamResult FROM COURSE AS C) SELECT CourseId, (SELECT COUNT (*) FROM TABLE (ER (ExamResult)) AS t) AS n FROM C_ER
Explanation
CREATE FUNCTION ER
(SM ROW ( StudentId SID, Mark INTEGER ) MULTISET )
RETURNS TABLE (StudentId SID, Mark INTEGER)
RETURN SM;
The type name TABLE ( StudentId SID, Mark INTEGER ) is actually just a synonym for ROW (StudentId SID, Mark INTEGER ) MULTISET). The misleading synonym is available only in a RETURNS clause and not as a parameter type, for example. So ER is actually a no-op, returning its input.
Managing Cursors The PL/SQL uses 2 types of cursors: implicit and explicit. The PL/SQL declares a cursor implicitly for all the SQL data manipulation statements, including th
BEGIN Parameter Description in pl sql: BEGIN: This keyword signals the beginning of the executable section of a PL/SQL block, that contains executable statements. The execut
Datatypes Every constant and variable has a datatype that specifies the storage format, constraints, and the valid range of values. The PL/SQL gives a variety of predefined dat
DECLARE : This keyword signals the beginning of the declarative section of the PL/SQL block, that contains local declarations. The Items declared locally exist only within the
If two relations R and S are joined, then the non matching tuples of both R and S are ignored in __________________.
Updating by insertion Syntax : INSERT INTO ENROLMENT VALUES (SID ('S4'), 'Devinder', CID ('C1'));
Enrolment was split - SQL Example shows how relvars IS_CALLED and IS_ENROLLED_ON can be derived from the original ENROLMENT relvar, using projection in the initial assignment
Attributes: Just similar to variable, an attribute is declared with a name and datatype. The name should be exclusive within the object type. The datatype can be any Oracle ty
Comparison Operators The Comparison operators can compare one expression to another. The outcome is always true, false, or null. Usually, you use a comparison operators in condi
CURRVAL and NEXTVAL The series is a schema object which generates the sequential numbers. Whenever you form a sequence, you can specify its primary value and an increment. T
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