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

Insert command in sql, INSERT Command in SQL Loosely speaking, INSERT...

INSERT Command in SQL Loosely speaking, INSERT takes the rows of a given source table and adds them to the specified target table, retaining all the existing rows in the targ

Develop a job management site, Lightweight system to provide and take info ...

Lightweight system to provide and take info from workers in the field and office, have basic design outlined already just require build and implementation Desired Skills CSS,

Closing a cursor - explicit cursor, Closing a Cursor The CLOSE stateme...

Closing a Cursor The CLOSE statements disable the cursor, and the result set becomes undefined. An illustration of the CLOSE statement as shown: CLOSE c1;

Manipulating collections-nested table examples, Manipulating Collections ...

Manipulating Collections Within PL/SQL, the collections add procedural power and flexibility. The biggest benefit is that your program can compute subscripts to process the spec

Iterative control:exit statements, EXIT The EXIT statement forces a loop...

EXIT The EXIT statement forces a loop to done unconditionally. Whenever an EXIT statement is encountered, the loop is done immediately and controls the passes to the next statem

Sql queries-oracle , 1- You can check attribute names from each table in D...

1- You can check attribute names from each table in DBF11 by running for example:  desc dbf11.Member;  desc dbf11.Agent;  desc dbf11.Producer; Because some attribute names in

Cursor variables, What Are Cursor Variables  ? The Cursor variables ar...

What Are Cursor Variables  ? The Cursor variables are like C or Pascal pointers that hold the memory location (address) of some item rather of the item itself. Therefore, decl

Named notation, Named Notation The second procedure call uses the name...

Named Notation The second procedure call uses the named notation. An arrow (=>) serve as the relationship operator that associates the formal parameter to the left of the arro

Cartesian product, Using a Join on 2 tables, select all columns and all row...

Using a Join on 2 tables, select all columns and all rows from the tables without the use of a Cartesian product. Query: SELECT * FROM EMPLOYEE1 JOIN CONTRACT ON EMPLOYEE

Null statement-sequential control, NULL Statement The NULL statement c...

NULL Statement The NULL statement clearly specifies in action; it does nothing other than to pass control to the next statement. It can, though, improve the readability. In a

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