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

Passing cursor parameters, Passing Cursor Parameters You use the OPEN ...

Passing Cursor Parameters You use the OPEN statement to pass the parameters to a cursor. Unless you want to accept the default values, each proper parameter in the cursor decl

Naming conventions-pl/sql, Naming Conventions The similar naming conventi...

Naming Conventions The similar naming conventions apply to all PL/SQL program items and units including the variables, cursors, constants, cursor variables, procedures, exception

Keyword & parameter description - exception_init pragma, Keyword & Paramete...

Keyword & Parameter Description: PRAGMA: These keywords signify that the statement is a pragma (i.e. compiler directive). The Pragmas are processed at the compile time, n

Parameter and keyword description - packages, Parameter and Keyword Descrip...

Parameter and Keyword Description: package_name: This construct identifies the package. AUTHID Clause: This determine whether all the packaged subprograms impleme

Block structure in pl/sql, Block Structure The PL/SQL is a block-struct...

Block Structure The PL/SQL is a block-structured language. That is, the fundamental units (procedures, anonymous blocks, and functions) that make up a PL/SQL program are logi

Using aliases-declarations in sql, Using Aliases The Select-list items f...

Using Aliases The Select-list items fetched from a cursor related with the %ROWTYPE should have simple names or, if they are expressions, should have aliases. In the example bel

Records - syntax, Records Records are the items of the type RECORD. The...

Records Records are the items of the type RECORD. The Records have exclusively named fields that can store the data values of various types. And hence, a record treat associate

Example of foreign key constraint - sql, Example of Foreign Key Constraint ...

Example of Foreign Key Constraint Example: Alternative formulation for 6.3 as a foreign key constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Must_be_enrolled_to_take_exam

Sql is a database language, SQL Is a Database Language: The commands g...

SQL Is a Database Language: The commands given to a DBMS by an application are written in the database language of the DBMS. The term data sublanguage is sometimes used instea

Dynamic sql - pl sql, Dynamic SQL: The Most PL/SQL programs do a predi...

Dynamic SQL: The Most PL/SQL programs do a predictable, specific job. For illustration, a stored procedure may accept an employee number and salary increase, and then update t

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