Order of evaluation-pl/sql expressions , PL-SQL Programming

Assignment Help:

Order of Evaluation

When you do not use the parentheses to specify the order of evaluation, the operator precedence determine the order. Now compare the expressions below:

NOT (valid AND done)         |       NOT valid AND done


When the Boolean variables valid and complete the value FALSE, the first expression yields TRUE. Though, the second expression yields FALSE as NOT has a higher precedence than AND. So, the second expression is equivalent to:

(NOT valid) AND done
In the example below, notice that if valid has the value FALSE, the entire expression yields FALSE regardless of the value of done:

valid AND done

Similarly, in the next illustration, when valid has the value TRUE, the entire expression yields TRUE regardless of the value of done:

valid OR done


Related Discussions:- Order of evaluation-pl/sql expressions

Constants and variables in pl sql, Constants and Variables:   You can...

Constants and Variables:   You can declare the constants and variables in the declarative section of any PL/SQL subprogram, block, or package. The Declarations allot the stor

Expression in assignment statement - pl sql, Expression: This is a ran...

Expression: This is a randomly complex combination of constants, variables, literals, operators, & function calls. The simplest expression consists of a single variable. If th

Example of cast operator - sql, Example of Cast Operator So long as C...

Example of Cast Operator So long as CAST is used as shown, we could obtain the total marks for each exam in similar fashion, using SUM (Mark) AS TotalMarks. However, this giv

Is null operator-comparison operators, IS NULL Operator The IS NULL oper...

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

Control structure, Control Structures The Control structures are the mo...

Control Structures The Control structures are the most important PL/SQL extension to the SQL. Not only does PL/SQL let you manipulate Oracle data, it lets you process the data

Sqls counterpart of the key words, SQLs counterpart of the key words: ...

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

Substitution and instantiation - sql, Substitution and Instantiation - SQL ...

Substitution and Instantiation - SQL It shows how NULL might appear in substitution for a parameter of a predicate and how it might thus participate in instantiation of that p

%rowcount, %ROWCOUNT When its cursor or cursor variable is opened, the...

%ROWCOUNT When its cursor or cursor variable is opened, the %ROWCOUNT is zeroed. Before the first fetch, the %ROWCOUNT yields 0. Afterward, it yields the number of rows fetche

Closing a cursor - explicit cursor, Closing a Cursor The CLOSE stateme...

Closing a Cursor The CLOSE statements disable the cursor, and the result set becomes undefined. An illustration of the CLOSE statement as shown: CLOSE c1;

Keyword & parameter description - exceptions, Keyword & Parameter Descripti...

Keyword & Parameter Description: WHEN: This keyword introduces the exception handler. You can have many exceptions execute the similar sequence of the statements by follo

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd