Example of table literal - sql, PL-SQL Programming

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).

Posted Date: 1/18/2013 2:14:25 AM | Location : United States







Related Discussions:- Example of table literal - sql, Assignment Help, Ask Question on Example of table literal - sql, Get Answer, Expert's Help, Example of table literal - sql Discussions

Write discussion on Example of table literal - sql
Your posts are moderated
Related Questions
Keyword & Parameter Description: WHEN: This keyword introduces the exception handler. You can have many exceptions execute the similar sequence of the statements by follo

Using Operator REF: You can retrieve refs by using the operator REF that, like VALUE, takes as its argument a correlation variable. In the illustration below, you retrieve one

Implicit Rollbacks Before execute the INSERT, UPDATE, or DELETE statement, the Oracle marks an implicit savepoint . When the statement fails, the Oracle rolls back to the save

WHEN or THEN Key Constraints Suppose a table has two columns representing a period of time throughout which the information conveyed by the other columns is recorded as having

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

Using ROLLBACK The ROLLBACK statements end the present transaction and undo any change made during the transaction. The Rolling back is helpful for two reasons. Firstly, if yo

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

Exceptions An exception is the runtime error or warning condition that can be predefined or user-defined. The Predefined exceptions are raised implicitly through runtime system

Bitmap Join Indexes - This feature will increase the performance and detains the size and format of your databases in data Character Semantics and Globalization -This featur

Advantages of Invoker Rights The Invoker-rights routines centralize the data retrieval. They are particularly helpful in applications which store data in various schemas. In su