Effects of null for table expression, PL-SQL Programming

Effects of NULL for Table Expression

Here's an important distinction between expressions denoting tables and expressions denoting multisets of rows: a table expression cannot evaluate to NULL, whereas a multiset expression can. Moreover, although a row expression can evaluate to NULL-for instance, CAST ( NULL AS ROW ( X INTEGER, Y INTEGER ) ) is a legal expression-NULL cannot appear as an element of the body of a table. Every element of the body of a table is indeed a row. However, if a table has a column whose declared type is a row type, then NULL might appear in place of a value for that column in some row of that table.

Posted Date: 1/18/2013 7:46:56 AM | Location : United States







Related Discussions:- Effects of null for table expression, Assignment Help, Ask Question on Effects of null for table expression, Get Answer, Expert's Help, Effects of null for table expression Discussions

Write discussion on Effects of null for table expression
Your posts are moderated
Related Questions
UPDATE Statement   The UPDATE statement transforms the values of the specified columns in one or more rows in the table or view. Syntax:

The SQL ‘CREATE TABLE' scripts for all the tables you have implemented. Note that your tables must correspond exactly to the ERD you have provided in 1. above, or you will lose ma

Avoid the NOT NULL Constraint In the PL/SQL, using the NOT NULL constraint incur a performance cost. Consider the illustration as shown below: PROCEDURE calc_m IS m NUMB

Difference between 9i & 10G When Oracle releases any new databases then it are having some discrepancy with them. But 10G is having much difference than oracle 9i has. Oracle

Oracle 10G new features:- Automatic Database Diagnostic Monitor System Advancements - these methods will provides several methods for extracting reports through the Automatic

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

Create a procedure named STATUS_SHIP_SP that allows a company to employee in the Shipping Department to update the status of an order to add shipping information. The BB_BASKETSTAT

Methods: In normal, a method is a subprogram declared in an object type specification using the keyword MEMBER or STATIC. The method cannot have similar name as the object typ

Package STANDARD The package named STANDARD defines the PL/SQL atmosphere. The package specification globally declares the exceptions, types, and subprograms that are available

CURRVAL and NEXTVAL The series is a schema object which generates the sequential numbers. Whenever you form a sequence, you can specify its primary value and an increment. T