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!
Biconditional - SQL
The biconditional p ↔ q can be expressed in Tutorial D by p = q and the same is true of SQL. The question then arises as to whether, in SQL, p = q is equivalent to (¬p ∨ q) ∧ (¬q ∨ p). This matter is investigated in the truth table of Figure.
Figure: SQL p = q ≡ (¬p ∨ q) ∧ (¬q ∨ p)
As you can see, the equivalence does hold in SQL, but only because SQL treats unknown as not equal to-i.e., not the same truth value as-itself ! This treatment of p = q is consistent with the general rule that applies when NULL is an operand of a comparison in SQL.
Quantification in SQL To quantify something, as the theory book has it, is to state its quantity, to say how many of it there are. For example, in Tutorial D the expression CO
Initializing and Referencing Collections Until you initialize a collection, a nested table or varray is automatically null (i.e. the collection itself is null, not its elements)
Role of Abstraction in pl/sql: The abstraction is a high-level description or model of a real-world entity. The Abstractions keep our daily lives convenient. They help us ca
Dynamic Ranges The PL/SQL lets you determine the loop range dynamically at run time, as the example below shows: SELECT COUNT(empno) INTO emp_count FROM emp; FOR i IN 1..emp_cou
Expression: This is a randomly complex combination of constants, variables, literals, operators, & function calls. The simplest expression consists of a single variable. If 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
i NEED TO CREATE 3 guiS IN pl/sql sERVER PAGE FORM
Problem: (a) Define the following terms: (i) data mining. (ii) OLAP. (b) Differentiate between snowflake schema and star schema. Support your answer with appropriate
Effects of NULL Operator As a general rule-but not a universal one-if NULL is an argument to an invocation of a system-defined read-only operator, then NULL is the result of t
Question: (a) The objective of query optimization is to choose the most efficient strategy for implementing a given relational query, thereby improving the system performance. On
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