Name resolution - pl/sql, PL-SQL Programming

Assignment Help:

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);


Related Discussions:- Name resolution - pl/sql

Iterative control: loop statement, Iterative Control: LOOP  Statements T...

Iterative Control: LOOP  Statements The LOOP statement executes a series of statements multiple times. There are 3 forms of LOOP statements: LOOP, WHILE-LOOP, & FOR-LOOP. LOOP

Cursor attributes in pl sql, Cursor Attributes   The Cursors and curso...

Cursor Attributes   The Cursors and cursor variables have 4 attributes which give you helpful information about the execution of a data manipulation statement. Syntax:

Create Tables, Hi there, I have the final part of a submission to do, it ...

Hi there, I have the final part of a submission to do, it is a demonstration that takes place tomorrow. I do not have to use previous information, but i have resources that sho

Update stock levels, At times, customers make mistakes in submitting their ...

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

Processing transactions, Processing Transactions This part describes ho...

Processing Transactions This part describes how to do the transaction processing. You learn the fundamental techniques that safeguard the consistency of your database, involvin

Need for dynamic sql - pl sql , Need for Dynamic SQL: You need dynamic...

Need for Dynamic SQL: You need dynamic SQL in the situations as follows: 1) You would like to execute a SQL data definition statement (like CREATE), a data control statemen

Calculate the total shopper spending, Many of the reports generated from th...

Many of the reports generated from the system calculate the total dollars in purchases for a shopper. Complete the following steps to create a function named TOT_PURCH_SF that acce

Manipulating objects in pl sql, Manipulating Objects: You can use an o...

Manipulating Objects: You can use an object type in the CREATE TABLE statement to indicate the datatype of a column. When the table is created once, you can use the SQL statem

Triggers, At times, customers make mistakes in submitting their orders and ...

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

Using limit - collection method, Using LIMIT For nested tables, that h...

Using LIMIT For nested tables, that have no maximum size, the LIMIT returns NULL. For varrays, the LIMIT returns the maximum number of elements that a varray can have (that yo

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