Cursor variables in pl sql, PL-SQL Programming

Assignment Help:

Cursor Variables:

 To execute the multi-row query, the Oracle opens an unnamed work region that stores the processing information. You can use an explicit cursor that names the work region, to access the information. Or, you can use the cursor variable that points to the work region. While a cursor always refers to similar query work region, a cursor variable can refer to various work regions. To create the cursor variables, you can define a REF CURSOR type, and then declare the cursor variables of that type.

The Cursor variables are such as C or Pascal pointers that hold the memory location (address) of a little item rather of the item itself. Therefore, declaring a cursor variable build a pointer, not an item.

1597_constant variable.png

Keyword and Parameter Description:

type_name:

This is a user-defined type specifier that is used in the subsequent declarations of the PL/SQL cursor variables.

REF CURSOR:

In PL/SQL, the pointers have datatype REF X, where REF is short form of REFERENCE and

X stands for the class of objects. And hence, the cursor variables have datatype REF CURSOR.

RETURN:

This keyword introduces the RETURN clause that specifies the datatype of the cursor variable result value. You can use the %ROWTYPE attribute in the RETURN clause to give a record type which presents a row in a database table or a row returned by a cursor or strongly typed cursor variable. You can also use the %TYPE attribute to give the datatype of a earlier declared record.

cursor_name:

These identify an explicit cursor earlier declared within the present scope.

cursor_variable_name:

These identify a PL/SQL cursor variable formerly declared within the present scope.

record_name:

These identify a user-defined record formerly declared within the present scope.

record_type_name:

These identify a RECORD type formerly defined within the present scope.

db_table_name:

These identify a database table (or view) that shuld be accessible when the declaration is elaborated.

%ROWTYPE:

These attributes provides a record type that presents a row in the database table or a row fetched from the cursor or strongly typed cursor variable. The Fields in the record and equivalent columns in the row have similar names and datatypes.

%TYPE:

These attributes provides the datatype of a formerly declared user-defined record.

 


Related Discussions:- Cursor variables in pl sql

Table represents an extension - sql, Table Represents an Extension - SQL ...

Table Represents an Extension - SQL It describes how each tuple in a relation represents a true instantiation of some predicate and each true instantiation is represented by s

Package standard in pl/sql, Package STANDARD package named STANDARD d...

Package STANDARD package named STANDARD defines the PL/SQL atmosphere. The package specification globally declares the exceptions, types, and subprograms that are available a

CURSOR, #quesWrite a cursor to open an employee database and fetch the empl...

#quesWrite a cursor to open an employee database and fetch the employee record whose age is greater than 45.tion..

Parameter aliasing, Parameter Aliasing   To optimize the subprogram ca...

Parameter Aliasing   To optimize the subprogram call, the PL/SQL compiler can decide between the two techniques of the parameter passing. With the by-value techniques, the v

Sql script to create and populate the tables, Create the four tables and po...

Create the four tables and populate them with the given data. Answer the following queries in SQL. 1. Get all part-color/part-city combinations. Note: Here and subsequently, the

Using %rowtype-declarations in sql, Using %ROWTYPE The %ROWTYPE attribut...

Using %ROWTYPE The %ROWTYPE attribute gives a record type which represents a row in a table (or view). The record can store the whole row of data selected from the table or fetc

Using exception_init - user-defined exceptions, Using EXCEPTION_INIT T...

Using EXCEPTION_INIT To handle unnamed internal exceptions, you should use the OTHERS handler or the pragma EXCEPTION_INIT. The pragma is a compiler directive that can be th

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

Like operator-comparison operators, LIKE Operator You use the LIKE opera...

LIKE Operator You use the LIKE operator to compare the character value to a pattern. The Case is significant. LIKE returns the Boolean value TRUE when the character patterns mat

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