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

Loop labels- iterative control, Loop Labels Like the PL/SQL blocks, loop...

Loop Labels Like the PL/SQL blocks, loops can also be labeled. The label, an undeclared identifier enclosed by double angle brackets, should appear at the beginning of the LOOP

Using set transaction, Using SET TRANSACTION You use the SET TRANSACTI...

Using SET TRANSACTION You use the SET TRANSACTION statement to begin the read-only or read-write transaction, start an isolation level, or assign your present transaction to a

I need sql data base, I need SQL Data Base Project Description: Netwo...

I need SQL Data Base Project Description: Network SQL database and SQL Setup two 4 workstation Skills required are Data Entry, MySQL, SQL

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:

Commit statement in pl sql, COMMIT Statement The COMMIT statement expli...

COMMIT Statement The COMMIT statement explicitly makes everlasting changes to the database during the present transaction. The Changes made to the database are not considered e

I need sql - wp sql expert, I need SQL , WP SQL Expert Project Descripti...

I need SQL , WP SQL Expert Project Description: Expert required to modify WP SQL query. Skills required are MySQL, SQL, PHP, Wordpress

Relational operators-comparison operators, Relational Operators The rela...

Relational Operators The relational operators permit you to compare randomly complex expressions. The list below provides the meaning of each operator:

Oracle PL SQL, I need to write one function and one procedure to query a Or...

I need to write one function and one procedure to query a Oracle 10.1 DB using PL SQL. I have the schema and exact queries...along with work Ive started and a template to put the a

Introduction to SQl and DQL, which operation is used if we are interested i...

which operation is used if we are interested in only certain columns of a table?

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