Name resolution-naming conventions, PL-SQL Programming

Assignment Help:

Name Resolution

In potentially uncertain SQL statements, the names of the database columns take precedence over the names of the local variables and formal parameters. For e.g. the DELETE statement removes all the employees from the emp table, not just ’KING’, as Oracle suppose that both enames in the WHERE clause refer to the


database column:
DECLARE
ename VARCHAR2(10) := ’KING’;
BEGIN
DELETE FROM emp WHERE ename = ename;
In such cases, to avoid the uncertainty, prefix the names of the local variables and formal parameters with my_, as shown below:

DECLARE
my_ename VARCHAR2(10);
Or, use a block label to qualify references, as in
<

>
DECLARE
ename VARCHAR2(10) := ’KING’;
BEGIN
DELETE FROM emp WHERE ename = main.ename;

The next illustration shows that you can use a subprogram name to qualify references to a local variables and formal parameters:

FUNCTION bonus (deptno IN NUMBER, ...) RETURN REAL IS
job CHAR(10);
BEGIN
SELECT ... WHERE deptno = bonus.deptno AND job = bonus.job;


Related Discussions:- Name resolution-naming conventions

Updating by replacement, Updating by replacement Syntax: UPDAT...

Updating by replacement Syntax: UPDATE ENROLMENT SET Name = 'Ann' WHERE StudentId = SID ('S1'); Note the use of SET, as already noted in connection with direct a

Write a stored procedure, a. Create a table odetails_new. It has all the a...

a. Create a table odetails_new. It has all the attributes of odetails and an additional column called cost, whose values are the product of the quantity and price of the part bein

Controlling autonomous transactions, Controlling Autonomous Transactions ...

Controlling Autonomous Transactions The first SQL statement in an autonomous routine starts a transaction. Whenever one transaction ends, the next SQL statement starts the oth

Package - pl/sql programming, What Is a Package? The package is a sch...

What Is a Package? The package is a schema object that group logically related PL/SQL items, types, and subprograms. The Packages usually have 2 parts, a specification & a bo

Functions in pl/sql, Functions   The function is a subprogram that cal...

Functions   The function is a subprogram that calculates a value. The Functions and procedures are structured similar, except that the functions have a RETURN clause. You can

Third step at defining type sid in sql, Third Step at defining type SID in ...

Third Step at defining type SID in SQL CREATE DOMAIN SID AS VARCHAR(5) CHECK ( VALUE IS NOT NULL AND SUBSTRING(VALUE FROM 1 FOR 1) = 'S' AND CAST('+'||SUBSTRING(VALUE

Select query, Query: SELECT * FROM EMPLOYEE1; Select 5 columns and ...

Query: SELECT * FROM EMPLOYEE1; Select 5 columns and all rows from one table Query: SELECT C_ID, COMPANY, BUILDING, DEPARTMENT, BRANCH FROM CONTRACT;

Comparison operators- pl/sql, Comparison Operators The Comparison operat...

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

Mutual recursion, Mutual Recursion The Subprograms are mutually recursi...

Mutual Recursion The Subprograms are mutually recursive if they directly or indirectly call each other. In the illustration below, the Boolean functions odd & even, that dete

Difference between 9i & 10g, Difference between 9i & 10G When Oracle r...

Difference between 9i & 10G When Oracle releases any new databases then it are having some discrepancy with them. But 10G is having much difference than oracle 9i has. Oracle

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