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Oracle PL/SQL Language Pocket Reference, 4th Edition
book

Oracle PL/SQL Language Pocket Reference, 4th Edition

by Steven Feuerstein, Bill Pribyl, Chip Dawes
October 2007
Intermediate to advanced content levelIntermediate to advanced
178 pages
2h 50m
English
O'Reilly Media, Inc.
Content preview from Oracle PL/SQL Language Pocket Reference, 4th Edition

Conditional and Sequential Control

PL/SQL includes conditional (IF, CASE) structures as well as sequential control (GOTO, NULL) constructs.

Conditional Control Statements

There are several varieties of IF-THEN-ELSE and CASE structures.

IF-THEN combination

IF condition THEN
   executable statement(s)
END IF;

For example:

IF caller_type = 'VIP' THEN
   generate_response('GOLD');
END IF;

IF-THEN-ELSE combination

IF condition THEN
   TRUE sequence_of_executable_statement(s)
ELSE
   FALSE/NULL sequence_of_executable_statement(s)
END IF;

For example:

IF caller_type = 'VIP' THEN
   generate_response('GOLD');
ELSE
   generate_response('BRONZE');
END IF;

IF-THEN-ELSIF combination

IF condition-1 THEN
   statements-1
ELSIF condition-N THEN
 statements-N
[ELSE
   ELSE statements]
END IF;

For example:

IF caller_type = 'VIP' THEN
   generate_response('GOLD');
ELSIF priority_client THEN
   generate_response('SILVER');
ELSE
   generate_response('BRONZE');
END IF;

CASE statement

There are two types of CASE statements: simple and searched.

A simple CASE statement is similar to an IF-THEN-ELSIF structure. The statement has a switch expression immediately after the keyword CASE. The expression is evaluated and compared to the value in each WHEN clause. The first WHEN clause with a matching value is executed, and then control passes to the next statement following the END CASE. For example:

CASE region_id
   WHEN 'NE' THEN
      mgr_name := 'MINER';
   WHEN 'SE' THEN
      mgr_name := 'KOOI';
   ELSE mgr_name := 'LANE';
END CASE;

If a switch expression evaluates to NULL, ...

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Publisher Resources

ISBN: 9780596514044Errata Page