Effect of anonymous columns, PL-SQL Programming

Assignment Help:

Effect of Anonymous Columns

Now, recall that a VALUES expression denotes a table with undefined column names. If an initial value is to be specified when a base table is created, column definitions have to be implied by that initial value, so the question arises, how can a VALUES expression provide the initial value for a base table? The answer is that you have to learn an extra syntactic construct for that purpose, shown in Example.

Example: Specifying an initial value for a base table.

CREATE TABLE ENROLMENT (StudentId, Name, CourseId)

AS (VALUES (SID ('S1'), 'Anne', CID ('C1')),

(SID ('S2'), 'Boris', CID ('C1')))

WITH DATA;

Explanation:

  1. (StudentId, Name, CourseId) provides the names, positionally corresponding to the anonymous columns of the AS table.
  2. WITH DATA specifies that the given table is indeed to be the initial value. Curiously, this is required, unless WITHOUT DATA is written instead, in which case the AS table serves only to determine the declared types of the columns of the base table.
  3. SQL does not allow constraints to be declared if AS is used in place of explicit column definitions.

Related Discussions:- Effect of anonymous columns

Deleting objects in pl sql, Deleting Objects You can use the DELETE st...

Deleting Objects You can use the DELETE statement to eradicate objects from an object table. To eradicate objects selectively, you use the WHERE clause, as shown below: BEG

Example of unwrap operator - sql, Example of UNWRAP Operator - SQL Exa...

Example of UNWRAP Operator - SQL Example here shows how unwrapping can be done in longhand in SQL. Example: Unwrapping in SQL Letting CONTACT_INFO_WRAPPED denote the res

Boolean values-assignments in pl/sql, Boolean Values Only the values TRU...

Boolean Values Only the values TRUE, FALSE, & NULL can be assigned to a Boolean variable. For illustration, given the declaration DECLARE done BOOLEAN; the following statements

Updating tables in sql, Updating Tables in SQL The topic of updating b...

Updating Tables in SQL The topic of updating by describing the assignment operator, ":=" in Tutorial D. SQL uses a different syntax for assignment, using the key word SET and

Assignment 4, I need a query for PL/SQL, selecting names with cursor, goes ...

I need a query for PL/SQL, selecting names with cursor, goes down the list, assigns usernames (initials001) based on initials in the name. If two names have same initials the user

Open-for statement, OPEN-FOR Statement The OPEN-FOR statements execute ...

OPEN-FOR Statement The OPEN-FOR statements execute the multi-row query related with a cursor variable. It also allocates the resources used by the Oracle to process the query a

Package standard, Package STANDARD The package named STANDARD defines t...

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

Program, heap sort program in pl/sql

heap sort program in pl/sql

Declaring a cursor, Declaring a Cursor The Forward references are not ...

Declaring a Cursor The Forward references are not allowed in the PL/SQL. Therefore, you must declare a cursor before referencing it in other statements. Whenever you declare a

Data types in sql - xml, Data Types in SQL - XML, Array, Row ...

Data Types in SQL - XML, Array, Row BINARY LARGE OBJECT for arbitrarily large bit strings. XML for XML documents and fragments. ARRAY types for arrays.

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