First step at defining type sid in sql, PL-SQL Programming

Assignment Help:

First Step at defining type SID in SQL

CREATE TYPE SID AS ( C VARCHAR(5) ) ;

Explanation:

  1. TYPE SID announces that a type named SID is being defined to the system.
  2. AS ( C VARCHAR(5) ) defines SID as a structured type, whose values are represented as a structure consisting in this case of just a single attribute, named C, of type VARCHAR(5). (The term attribute here is not be confused with its use in relational theory.) The attribute definition C VARCHAR(5) causes an operator to come into existence that takes a value, of type SID and returns the value of the C component of s. The operator, SQL's counterpart of THE_C, is invoked using dot notation: s.C and is termed the observer function for the component C.

So-called constructor function, in this case a niladic operator named SID, is generated by the structure definition, such that SID() denotes the value of type SID whose only component is the "default value" for the attribute C, probably NULL. SID selector we need to use the so-called mutator function for the attribute C, which is also invoked using dot notation: SID().C('S1'). The mutator function takes a value of type SID as its left operand and a value of the declared type of C as its right operand (in parentheses). In general, if s is a value of type SID, then s.C('S1') denotes the SID value that is obtained from s by replacing its C component by the string 'S1'. If s had any other components (it doesn't, of course), they would be retained in s.C('S1'). By the way, don't be misled by the term "mutator": an SQL mutator function is a read-only operator.


Related Discussions:- First step at defining type sid in sql

Create GUIs in PL/SQL, i NEED TO CREATE 3 guiS IN pl/sql sERVER PAGE FORM

i NEED TO CREATE 3 guiS IN pl/sql sERVER PAGE FORM

Grouping and ungrouping in sql, Grouping and Ungrouping in SQL Example...

Grouping and Ungrouping in SQL Example specifying EXAM_MARK in place of COURSE in the main FROM clause. Example: Obtaining C_ER2 from EXAM_MARK SELECT CourseId, CAST

Python function, This task involves developing some functions that extract ...

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 subqueries, Using Subqueries A subquery is a query (typically ...

Using Subqueries A subquery is a query (typically enclosed by parentheses) that appears within another SQL data manipulation statement. If evaluated, the subquery gives a va

Seeking a programmer to design a legal document, Seeking a programmer to de...

Seeking a programmer to design a legal document with pre-existing fields that could allow the auto-population of client(s) information (i.e. Name, Account Number, Address etc.) int

Defining records, Defining and Declaring Records To create records, yo...

Defining and Declaring Records To create records, you have to define a RECORD type, and then declare records of that type. You may also define RECORD types in the declarative

Using operator ref - manipulating objects pl sql, Using Operator REF: ...

Using Operator REF: You can retrieve refs by using the operator REF that, like VALUE, takes as its argument a correlation variable. In the illustration below, you retrieve one

Difference between ttitle and btitle, TTITLE and BTITLE are commands in Pl-...

TTITLE and BTITLE are commands in Pl-SQL to control report headings and footers. This Ttitle & Btitle are mainly used on creating SQL*PLUS report. Ttitle is used for toptitle headi

Oracle 9i features, Bitmap Join Indexes - This feature will increase th...

Bitmap Join Indexes - This feature will increase the performance and detains the size and format of your databases in data Character Semantics and Globalization -This featur

Update command- sql, UPDATE Command- SQL Loosely speaking, UPDATE chan...

UPDATE Command- SQL Loosely speaking, UPDATE changes some of the column values of some existing rows of its target table. Thus, although some rows disappear from the target an

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