Effects of null for multiple assignments - sql, PL-SQL Programming

Assignment Help:

Effects of NULL for Multiple Assignments - SQL

If the row expression given as the source for a multiple assignment evaluates to NULL, then NULL is assigned to each target. If a SELECT ... INTO statement results in an empty table, then the target variables are not updated and a completion condition is given to indicate that. This is not exactly an "effect of NULL", of course, but I mention it here because of the contrast with a row subquery, which delivers a single row with NULL for each field when its table expression evaluates to an empty table. This observation might influence the choice between SET and SELECT ... INTO.


Related Discussions:- Effects of null for multiple assignments - sql

Sequential control - pl/sql, Sequential Control Dissimilar to the IF and ...

Sequential Control Dissimilar to the IF and LOOP statements, the GOTO and NULL statements are not important to the PL/SQL programming. The configuration of PL/SQL is such that th

Sql query on hospital database, Perform the following queries on the Hospit...

Perform the following queries on the Hospital1.DB using SQL Anywhere (START EARLY!). a. Which patients have purchased the drug "Tylenol"? List the names and addresses. Arrange the

Updating variables, Updating Variables For assignment, SQL uses the ke...

Updating Variables For assignment, SQL uses the key word SET, as in SET X = X + 1 (read as "set X equal to X+1") rather than X: = X + 1 as found in many computer languages.

Using limit - collection method, Using LIMIT For nested tables, that h...

Using LIMIT For nested tables, that have no maximum size, the LIMIT returns NULL. For varrays, the LIMIT returns the maximum number of elements that a varray can have (that yo

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

Enforce security in the database system, Question: (a) In the context o...

Question: (a) In the context of database security explain how the following database features help to enforce security in the database system: (i) Authorisation (ii) Access

Implicit cursor attributes, Implicit Cursor Attributes The Implicit cur...

Implicit Cursor Attributes The Implicit cursor attributes returns the information about the execution of an INSERT, DELETE, UPDATE, or SELECT INTO statement. The cursor attribu

Magento change address format depending on store, Magento change address fo...

Magento change address format depending on store Project Description: What I need is that depending on the store in which the customer bought the address should change the fo

Anatomy of a command, Anatomy of a Command Figure, showing a simple S...

Anatomy of a Command Figure, showing a simple SQL command, is almost identical to its counterpart in the theory book. The only difference arises from the fact that SQL uses a

Transaction context, Transaction context As the figure shows, the majo...

Transaction context As the figure shows, the major transaction shares its context with the nested transactions, but not with the autonomous transactions. Similarly, If one aut

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