Rephrase Conditional Control Statements

When computing a logical expression, the PL/SQL uses short-circuit evaluation. That is, the PL/SQL stops evaluating the expression as soon as the result can be determined. For illustration, in the OR expression below, when the value of sal is less than 1500, the left operand yields TRUE, Therefore PL/SQL need not evaluate the right operand (as OR returns TRUE if either of its operands is true):

IF (sal < 1500) OR (comm IS NULL) THEN

...

END IF;

Now, consider the AND expression shown below:

 

IF credit_ok(cust_id) AND (loan < 5000) THEN

...

END IF;

The Boolean function credit_ok is forever called. Though, if you switch the operands of AND as shown:

 

IF (loan < 5000) AND credit_ok(cust_id) THEN

...

END IF;

The function is called only if the expression loan < 5000 is true (as AND returns TRUE only if both its operands are true). The similar idea applies to the EXIT-WHEN statements.

Posted Date: 10/5/2012 5:01:48 AM | Location : United States

Ask an Expert

Related Discussions:- Rephrase conditional control statements, Assignment Help, Ask Question on Rephrase conditional control statements, Get Answer, Expert's Help, Rephrase conditional control statements Discussions

Write discussion on Rephrase conditional control statements
Your posts are moderated

Write your message here..

Related Questions

Referencing records, Referencing Records Unlike the elements in a coll... Referencing Records Unlike the elements in a collection, that are accessed using subscripts, the fields in a record are accessed by name. To reference an individual field, you

How pl/sql resolves the calls? , How Calls Are Resolved? The figure sho... How Calls Are Resolved? The figure shows that how the PL/SQL compiler resolves the subprogram calls. When the compiler encounters the procedure or function call, it tries to di

Overloading method in pl/sql, Overloading: Similar to packaged subprog... Overloading: Similar to packaged subprograms, methods of the same type can be overloaded. That is, you can use similar name for various methods if their formal parameters diff

Delete statement - syntax, DELETE Statement The DELETE statement elimin... DELETE Statement The DELETE statement eliminates whole rows of data from the specified table or view. Syntax:

Keyword and parameter description - if statement, Keyword and Parameter Des... Keyword and Parameter Description: boolean_expression: This is an expression which results the Boolean value TRUE, FALSE, & NULL. It is related with a series of statement

Loop statements, LOOP Statements The LOOP statements execute a series o... LOOP Statements The LOOP statements execute a series of statements at multiple times. The loops enclose the series of statements that is to be repeated. The PL/SQL provides typ

Develop data business intelligence project, Develop Data Business Intellige... Develop Data Business Intelligence Project Project Description: We are linking our Microsoft SQL Database to GoodData Business Intelligence. We are seeking somebody who has e

Primary key - sql, Primary Key - SQL A PRIMARY KEY specification carri... Primary Key - SQL A PRIMARY KEY specification carries an implicit NOT NULL constraint on each column of the specified key. When more than one key constraint is required, the k

Declare keyword description in pl sql, DECLARE : This keyword signals t... 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

Using operator deref - manipulating objects in pl sql, Using Operator DEREF... Using Operator DEREF: You cannot navigate through refs within the PL/SQL procedural statements. Rather than, you should use the operator DEREF in the SQL statement. The DEREF