Referencing records, PL-SQL Programming

Assignment Help:

Referencing Records

Unlike the elements in a collection, that are accessed using subscripts, the fields in a record are accessed by name. To reference an individual field, you can use the dot notation and the syntax which is as shown:

record_name.field_name

For illustration, you reference field hire_date in record emp_info as shown:

emp_info.hire_date ...

When calling a function which returns a user-defined record, use the syntax below to reference the fields in the record:

function_name(parameter_list).field_name

For illustration, the call to function nth_highest_sal references to the field salary in record emp_info:

DECLARE

TYPE EmpRec IS RECORD (

emp_id NUMBER(4),

job_title CHAR(14),

salary REAL(7,2));

middle_sal REAL;

FUNCTION nth_highest_sal (n INTEGER) RETURN EmpRec IS

emp_info EmpRec;

BEGIN

...

RETURN emp_info; -- return record

END;

BEGIN

middle_sal := nth_highest_sal(10).salary; -- call function

When calling a parameter less function, following syntax can be use:

function_name().field_name -- note empty parameter list

To reference the nested fields in a record returned by a function, use the extended dot notation. The syntax is as shown:

function_name(parameter_list).field_name.nested_field_name

For illustration, the following call to function item references to the nested field minutes in record item_info:

DECLARE

TYPE TimeRec IS RECORD (minutes SMALLINT, hours SMALLINT);

TYPE AgendaItem IS RECORD (

priority INTEGER,

subject VARCHAR2(100),

duration TimeRec);

FUNCTION item (n INTEGER) RETURN AgendaItem IS

item_info AgendaItem;

BEGIN

...

RETURN item_info; -- return record

END;

BEGIN

...

IF item(3).duration.minutes > 30 THEN ... -- call function

END;


Related Discussions:- Referencing records

Example of using aggregation on nested tables, Example of Using Aggregation...

Example of Using Aggregation on Nested Tables Example: How many students sat each exam WITH C_ER AS (SELECT CourseId, CAST (TABLE (SELECT DISTINCT StudentId, Mark FROM EXAM

Recursive subprograms, Recursive Subprograms The recursive subprogram ...

Recursive Subprograms The recursive subprogram is the one that calls itself. Think of a recursive call as a call to a few other subprograms that does the similar task as your

Data abstraction, Data Abstraction The Data abstraction extracts the im...

Data Abstraction The Data abstraction extracts the important properties of data while ignoring the not necessary details. Once you design a data structure, you can fail to reme

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

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

Methods in pl/sql, Methods: In normal, a method is a subprogram declar...

Methods: In normal, a method is a subprogram declared in an object type specification using the keyword MEMBER or STATIC. The method cannot have similar name as the object typ

%type - cursors, %TYPE: This attribute gives the datatype of a formerly...

%TYPE: This attribute gives the datatype of a formerly declared collection, cursor variable, object, field, record, database column, or variable. Datatype: This is simply

Sql scripts, The SQL ‘CREATE TABLE' scripts for all the tables you have imp...

The SQL ‘CREATE TABLE' scripts for all the tables you have implemented. Note that your tables must correspond exactly to the ERD you have provided in 1. above, or you will lose ma

%rowtype - cursors, %ROWTYPE: This attribute gives a record type which ...

%ROWTYPE: This attribute gives a record type which represents a row in the database table or a row fetched from a formerly declared cursor. The Fields in the record and corresp

Raise_application_error, Raise_application_error -  procedure of package D...

Raise_application_error -  procedure of package DBMS_STANDARD , allows to issue an user_defined error messages by stored sub-program or database trigger.

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