Example of table literal - sql, PL-SQL Programming

Assignment Help:

Example of Table Literal - SQL

Example: A Table Literal (correct version)

VALUES

('S1', 'C1', 'Anne'),

('S1', 'C2', 'Anne'),

('S2', 'C1', 'Boris'),

('S3', 'C3', 'Cindy'),

('S4', 'C1', 'Devinder')

Now, the question arises, what is the (table) type of the table shown in Example? For that matter, what is the (row) type of ('S1', 'C1', and 'Anne')? In particular, what are the field names of those three fields, which would become column names for the containing table? The short answer is that they are determined by the context in which the expression appears. Because the components are distinguished anyway by ordinal position, the field names sometimes serve little or no purpose. In fact several fields are permitted to acquire the same name. Also, sometimes the context does not provide any names at all, in which case, according to the standard, each field is assigned a unique but unpredictable name.

Examples arising as we go along will make this issue a little clearer. I shall use the term anonymous column to refer to a column whose name is unpredictable and therefore effectively undefined. Note carefully that if the word ROW is omitted and the row consists of a single field, then the parentheses can also be omitted. Thus, VALUES 'S1' denotes a table consisting of a single column and a single row, the SQL counterpart of RELATION { TUPLE { StudentId 'S1' } } (though the SQL counterpart has nothing corresponding to the attribute name).


Related Discussions:- Example of table literal - sql

Mysql developer/programmer, Project Description: I want somebody who can...

Project Description: I want somebody who can help me with an idea that I have been working on for a few months now. The person will require extensive knowledge of warcraft 3 PvP

Short-circuit evaluation-pl/sql expressions , Short-Circuit Evaluation ...

Short-Circuit Evaluation When computing a logical expression, the PL/SQL uses short-circuit evaluation. That is, the PL/SQL stops computing the expression as soon as the result

Number types in pl/sql, Number Types The Number types permit you to sto...

Number Types The Number types permit you to store the numeric data (real numbers, integers, and floating-point numbers), show quantities, and do computations. BINARY_INTEG

Sql cursor - syntax, SQL Cursor   The Oracle implicitly opens a cursor...

SQL Cursor   The Oracle implicitly opens a cursor to process each SQL statement not related with an explicit cursor. The PL/SQL refers to the most current implicit cursor as t

Exit statement - syntax, EXIT Statement   You can use the EXIT stateme...

EXIT Statement   You can use the EXIT statement to exit a loop. The EXIT statement has 2 forms: the conditional EXIT WHEN and the unconditional EXIT. With the either form, you

Recursive subprograms, Recursive Subprograms The recursive subprogram ...

Recursive Subprograms The recursive subprogram is the one that calls itself. Think of a recursive call as a call to a few other subprograms that does the similar task as your

Variable declaration - sql, Variable Declaration - SQL SQL's support f...

Variable Declaration - SQL SQL's support for variables is very similar to Tutorial D's, except that the syntax for creating persistent  variables-base tables-is quite differen

Using operator deref - manipulating objects in pl sql, Using Operator DEREF...

Using Operator DEREF: You cannot navigate through refs within the PL/SQL procedural statements. Rather than, you should use the operator DEREF in the SQL statement. The DEREF

While-loop - iterative control, WHILE-LOOP The WHILE-LOOP statement rela...

WHILE-LOOP The WHILE-LOOP statement relates a condition with the series of statements enclosed by the keywords LOOP and END LOOP, as shown: WHILE condition LOOP sequence_of_sta

Subprograms, Subprograms The PL/SQL has two types of subprograms known ...

Subprograms The PL/SQL has two types of subprograms known as the procedures and functions that can take parameters and be invoked. As the following example represents, a subp

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