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

How bulk bind helps improvement in performance?, How Bulk Binds Improve Per...

How Bulk Binds Improve Performance The assigning of values to the PL/SQL variables in SQL statements is known as binding. The binding of the whole collection at once is know

Use of table expressions - expressing constraint conditions, Use of Table E...

Use of Table Expressions - Expressing Constraint Conditions With the exception of key constraints, the examples in the theory book all explicitly reference at least one relvar

Calculating a Shopper''s Total Spending, Many of the reports generated from...

Many of the reports generated from the system calculate the total dollars in a shopper''s purchases. Follow these steps to create a function named TOT_PURCH_SF that accepts a shopp

Varrays versus nested tables, Varrays versus Nested Tables The Nested ta...

Varrays versus Nested Tables The Nested tables are differing from varrays in the following ways: 1)  Varrays have a maximum size, while nested tables do not. 2)  Varrays are

Predicate - sql, Predicate - SQL Consider the declarative sentence-a p...

Predicate - SQL Consider the declarative sentence-a proposition-that is used to introduce this topic:  "Student S1, named Anne, is enrolled on course C1." Recall that th

Parameter and keyword description - update statement, Parameter and Keyword...

Parameter and Keyword Description:   table_reference: This keyword identifies the table or view that should be accessible when you execute the UPDATE statement, and for wh

Manipulating local collections - pl/sql, Manipulating Local Collections ...

Manipulating Local Collections Within PL/SQL, to manipulate the local collection, by using the  TABLE and CAST operators . The operands of CAST are a collection declared locally

Using forall statement - bulk bind performance improvement, Using the FORAL...

Using the FORALL Statement The keyword FORALL instruct the PL/SQL engine to bulk-bind input collections before sending them all to the SQL engine. Though the FORALL statement

Write a program, to write a heap sort program usin pl-sql

to write a heap sort program usin pl-sql

Wrapping and unwrapping in sql, Wrapping and unwrapping in SQL Operato...

Wrapping and unwrapping in SQL Operators WRAP and UNWRAP in connection with attributes whose declared types are tuple types. Example shows how extension and projection can be

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