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

Biconditional - sql, Biconditional - SQL The biconditional p ↔ q can b...

Biconditional - SQL The biconditional p ↔ q can be expressed in Tutorial D by p = q and the same is true of SQL. The question then arises as to whether, in SQL, p = q is equiv

Using rename in combination with join - sql, Using RENAME in combination wi...

Using RENAME in combination with JOIN - SQL Example gives pairs of ids of students having the same name, by joining two renamings of IS_CALLED. Example gives an equivalent ex

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

Explicit cursor attributes, Explicit Cursor Attributes The cursor varia...

Explicit Cursor Attributes The cursor variable or each cursor has four attributes: %FOUND, %ISOPEN, %ROWCOUNT, and %NOTFOUND. When appended to the cursor or cursor variable, th

In packages - subprograms, In Packages The Forward declarations also g...

In Packages The Forward declarations also group logically related subprograms in the package. The subprogram specifications go in the package specification, & the subprogram b

Use the pls_integer datatype - performance of application, Use the PLS_INTE...

Use the PLS_INTEGER Datatype When you require to declare an integer variable, use the datatype PLS_INTEGER that is the most efficient numeric type. That is as the PLS_INTEGER

Stored subprograms, Stored Subprograms Normally, tools (like Oracle Fo...

Stored Subprograms Normally, tools (like Oracle Forms) which incorporate the PL/SQL engine can store subprograms locally for later, strictly local execution. Though, to become

Sql pseudocolumns, SQL Pseudocolumns The PL/SQL recognizes the followin...

SQL Pseudocolumns The PL/SQL recognizes the following SQL pseudocolumns, that returns the specific data items: LEVEL, NEXTVAL, CURRVAL, ROWID, & ROWNUM. The Pseudocolumns are n

Program, heap sort program in pl/sql

heap sort program in pl/sql

Updating by insertion, Updating by insertion Syntax : INSERT IN...

Updating by insertion Syntax : INSERT INTO ENROLMENT VALUES (SID ('S4'), 'Devinder', CID ('C1'));

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