Type versus representation confusion in sql, PL-SQL Programming

Type versus Representation Confusion in SQL

This describes how a value might have two or more distinct representations. For example, user-defined type POINT might have a declared possrep based on Cartesian coordinates and another based on polar coordinates. SQL has a system-defined type, TIMESTAMP, for values representing points in time, a timestamp being represented by a date, a time of day, and-optionally-a time zone, expressed as a displacement from UTC. Clearly any timestamp can be expressed in several different ways, using different time zones.

Three o'clock in the afternoon of December 31st, 2011 in UK, for example, is the same time as two o'clock in the morning of January 1st, 2012 in New Zealand. SQL treats those two representations as distinct values that compare equal, in like fashion to its treatment of character strings with trailing blanks, with similar consequences. If instead it had treated them as distinct representations of the same value, then the issue of indeterminacy would not have arisen.

Posted Date: 1/18/2013 2:41:12 AM | Location : United States







Related Discussions:- Type versus representation confusion in sql, Assignment Help, Ask Question on Type versus representation confusion in sql, Get Answer, Expert's Help, Type versus representation confusion in sql Discussions

Write discussion on Type versus representation confusion in sql
Your posts are moderated
Related Questions
Fetching Across Commits The FOR UPDATE clauses acquire exclusive all row locks. All rows are locked when you open the cursor, and when you commit your transaction they are unl

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.

Literature review

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

Declaring and Initializing Objects: An object type is once defined and installed in the schema; you can use it to declare the objects in any PL/SQL, subprogram, block or packa

MERGE and TRUNCATE in SQL SQL has two more table update operators, MERGE and TRUNCATE. MERGE, like INSERT, takes a source table s and uses it to update a target table t. Brief

Use External Routines The PL/SQL is particular for the SQL transaction processing. Therefore, several tasks are more quickly completed in a lower-level language like C that is

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

Define basic operators of relational algebra with an example each

Architecture The PL/SQL run-time system and compilation is a technology, not an independent product. Consider this technology as an engine that compiles and executes the PL/SQL