Name resolution - pl/sql, PL-SQL Programming

Name Resolution 

During the compilation, the PL/SQL compiler relates identifiers like the name of a variable with an address or memory location, actual value, or datatype. This process is termed as the binding. The relationship lasts through all the successive executions until the recompilation occurs, which may cause the rebinding.

Before binding the names, the PL/SQL should solve all the references to them in the compilation unit. This process is known as the name resolution. The PL/SQL considers all the names to be in the same namespace. Therefore, one declaration or definition in an inner scope can hide the other in an outer scope. In the illustration below, the declaration of the variable client hides the definition of the datatype Client as the PL/SQL is not case sensitive apart from within the string literals:

BEGIN

<>

DECLARE

TYPE Client IS RECORD (...);

TYPE Customer IS RECORD (...);

BEGIN

DECLARE

client Customer; -- hides definition of type Client

-- in outer scope

lead1 Client; -- illegal; Client resolves to the

-- variable client

lead2 block1.Client; -- OK; refers to type Client

BEGIN

NULL;

END;

END;

END;

Though, you can still refer to the datatype Client by qualifying the reference with the block label block1.

In the CREATE TYPE person1 statement below, the compiler solves the second reference to the manager as the name of the attribute you are trying to declare. In the CREATE TYPE person2 declaration, the compiler solves the second reference to the manager as the name of the attribute you merely declared. In both the situation, the reference to the manager generates an error as the compiler expects a type name.

CREATE TYPE manager AS OBJECT (dept NUMBER);

CREATE TYPE person1 AS OBJECT (manager manager);

CREATE TYPE person2 AS OBJECT (manager NUMBER, mgr manager);

Posted Date: 10/8/2012 8:15:00 AM | Location : United States







Related Discussions:- Name resolution - pl/sql, Assignment Help, Ask Question on Name resolution - pl/sql, Get Answer, Expert's Help, Name resolution - pl/sql Discussions

Write discussion on Name resolution - pl/sql
Your posts are moderated
Related Questions
At times, customers make mistakes in submitting their orders and call to cancel the order. Brewbean's wants to create a trigger that automatically updates the stock level of all pr

Sequential Control Dissimilar to the IF and LOOP statements, the GOTO and NULL statements are not important to the PL/SQL programming. The configuration of PL/SQL is such that th

This task involves developing some functions that extract data from an SQL database. The scenario is that a company which owns an online vehicle search website wants to generate so

Using the Collection Methods The collection methods below help to generalize the code and make collections easier to use and also make your applications easier to maintain:

What is Cursors how to use it in Real time application ?

Effects of NULL for Table Expression Here's an important distinction between expressions denoting tables and expressions denoting multisets of rows: a table expression cannot

What are the rates for help in writing PL/SQL procedures and functions?

Synonyms You can create the synonyms to provide location transparency for the remote schema objects like tables, views, sequences, stand-alone subprograms, and packages. Though,

Data Types and Representations This explains the concept possible representation, abbreviated possrep, and explains how these can be used in conjunction with constraints to de

Predefined Exceptions The internal exception is raised implicitly whenever your PL/SQL program exceeds a system-dependent limit or violates an Oracle rule. Each & every Oracle