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!
Pl/sql Conditional Control: IF statementsFrequently, it is necessary to take the alternative actions depending on the circumstances. The IF statement execute a series of statements conditionally. That is, whether the series is executed or not depends on the value of the condition. There are 3 forms of IF statements: IF-THEN, IF-THEN-ELSE, & IF-THEN-ELSIF.IF-THENThe simplest form of the IF statement acquaintances a condition with a series of statements enclosed by the keywords THEN and END IF (not ENDIF), as shown below:IF condition THENsequence_of_statementsEND IF;The series of statements is executed only if the condition is true. When the condition is false or null, then the IF statement can do nothing. In either of the case, the control passes to the next statement. An illustration is shown below:IF sales > quota THENcompute_bonus(empid);UPDATE payroll SET pay = pay + bonus WHERE empno = emp_id;END IF;You may want to place brief IF statements on a single line, as inIF x > y THEN high := x; END IF;IF-THEN-ELSEThe IF statement that is the second form adds the keyword ELSE follow by an alternative series of statements is as shown below:IF condition THENsequence_of_statements1ELSEsequence_of_statements2END IF;The series of statements in the ELSE clause is executed only if the condition is false or null. Therefore, the ELSE clause ensure that a sequence of statements is executed. In the example below, the first UPDATE statement is executed if the condition is true, while the second UPDATE statement is executed if the condition is false or null:IF trans_type = ’CR’ THENUPDATE accounts SET balance = balance + credit WHERE...ELSEUPDATE accounts SET balance = balance - debit WHERE...END IF;The THEN and ELSE clauses can involve the IF statements. That is, the IF statements can be nested, as the example below shows:IF trans_type = ’CR’ THENUPDATE accounts SET balance = balance + credit WHERE...ELSEIF new_balance >= minimum_balance THENUPDATE accounts SET balance = balance - debit WHERE ...ELSERAISE insufficient_funds;END IF;END IF;IF-THEN-ELSIFAt many times you want to select an action from some mutually exclusive alternatives. The third form of the IF statement uses the keyword ELSIF to introduce the additional conditions which is as shown below:IF condition1 THENsequence_of_statements1ELSIF condition2 THENsequence_of_statements2ELSEsequence_of_statements3END IF;When the first condition is false or null, then the ELSIF clause tests another condition. An IF statement can have a few number of ELSIF clauses; the final ELSE clause is elective. The Conditions are evaluated one by one from top to bottom. When any condition is true, its related sequence of statements is executed and the control passes to the next statement. If all the conditions are false or null, then the sequence in the ELSE clause is executed. Consider the following illustration as shown below:BEGIN...IF sales > 50000 THENbonus := 1500;ELSIF sales > 35000 THENbonus := 500;ELSEbonus := 100;END IF;INSERT INTO payroll VALUES (emp_id, bonus, ...);END;When the value of sales is bigger than 50000, the first and second conditions are true.However, bonus is assigned the proper value of 1500 as the second condition is never tested. When the first condition is true, its related statement is executed and the control passes to the INSERT statement.
Explicit Cursor Attributes The cursor variable or each cursor has four attributes: %FOUND, %ISOPEN, %ROWCOUNT, and %NOTFOUND. When appended to the cursor or cursor variable, th
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
Write an anonymous block that contains a PL/SQL procedure. The procedure takes two input parameter: oldZip and newZip, and it updates the zipcodes table by replacing all oldZip wit
Example of Table Literal - SQL Example: A Table Literal (correct version) VALUES ('S1', 'C1', 'Anne'), ('S1', 'C2', 'Anne'), ('S2', 'C1', 'Boris'), ('S3', 'C3'
Collection Methods: The collection method is a built-in function or procedure which operates on the collections and is called using the dot notation. The methods like the C
Existential Quantification - SQL Existential quantification-stating that something is true of at least one object under consideration-can be expressed by OR(r,c), meaning tha
%ROWCOUNT The %ROWCOUNT yields the number of rows affected by the INSERT, UPDATE, or DELETE statement, or returned by a SELECT INTO statement. The %ROWCOUNT yields zero when a
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;
Example of WRAP Operator - SQL The effect of Example can be obtained in SQL but note that one needs to write down not only the names of the columns being wrapped but also the
DELETE Statement The DELETE statement eliminates whole rows of data from the specified table or view. Syntax:
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