This document discusses using Oracle server features in Forms applications. It describes useful server features like constraints, triggers, and stored program units. It also covers handling PL/SQL code, trapping server errors, and performing DDL commands using the FORMS_DDL built-in subprograms. Supported PL/SQL8 features in Forms are also identified.

1. Using Oracle Server Features In Forms
http://blog.ebiztechnics.com

2. Objectives
• Use Oracle server functionalities in forms
• Deal with server-side PL/SQL
• Recognize which PL/SQL8 features are supported in forms
• Handle Oracle server errors
• Perform DDL commands by using the FORMS_DDL built in
subprograms
http://blog.ebiztechnics.com

3. Oracle Server Features
Useful Oracle server features:
• Declarative constraints
• Stored program units
• Database triggers
• DDL
http://blog.ebiztechnics.com

4. Dealing with PL/SQL Code
• Where to store PL/SQL code:
– On the Oracle server
– In the attached PL/SQL libraries
– In the form itself
• Where to call PL/SQL code:
– From database triggers
– From forms triggers
• Application partitioning
http://blog.ebiztechnics.com

5. PL/SQL8 Support in Forms
• Client-side program units cannot support Oracle8i object-related
functionality.
• Stored program units can use PL/SQL8 features.
http://blog.ebiztechnics.com

6. PL/SQL8 Scalar Types
• NCHAR and NVARCHAR2
• SIGNTYPE
• FLOAT
• NATURALN
• POSITIVEN
• PLS_INTEGER
http://blog.ebiztechnics.com

7. Unsupported Client-side PL/SQL Features
• Untrusted external procedures
• Object types
• Collection types
• LOB types
• Methods
• Objects as stored procedure parameters
http://blog.ebiztechnics.com

8. Causes for Oracle Server Errors
Base Table Block
Implicit DML
Trigger/PU
Explicit DML
Stored PU call
Form Oracle Server
Declarative
Constraints
Database
Triggers
Program
Units
http://blog.ebiztechnics.com

9. Trapping Server Errors
Base table block
On-Error:
DBMS_ERROR_CODE
DBMS_ERROR_TEXT
Explicit DML/PU call
When Others:
SQLCODE
SQLERRM
Constraint
DB trigger
Stored PU
Form Oracle Server
Predefined
message
RAISE_APPLICATION_
ERROR
RAISE_APPLICATION_
ERROR
http://blog.ebiztechnics.com

10. FORMS_DDL Built-in
• Syntax: FORMS_DDL (statement);
• Parameter must be<=32K
• Can pass PL/SQL block, DML or DDL statement
• Characteristics:
– Unrestricted; valid in Enter Query mode
– Statement must not contain bind-
variable references
http://blog.ebiztechnics.com

11. FORMS_DDL Built-in
• Characteristics:
– Statement cannot return results directly
– Use FORM_SUCCESS to check
success of statement
• Hints:
– Create SQL Query record group
instead of FORMS_DDL for better performance.
– Call stored program unit instead of FORMS_DDL
http://blog.ebiztechnics.com

12. FORMS_DDL Example
Example 1: Create a table
FORMS_DDL(‘CREATE TABLE t (x number(5))’);
IF not FORM_SUCCESS THEN
MESSAGE(‘Table creation Failed…’);
END IF;
Example: 2: Execute Procedure with given name:
FORMS_DDL (‘BEGIN ‘ || p_name ||‘; END; ‘);
IF not FORM_SUCCESS THEN
message(DBMS_ERROR_CODE||’ ‘||
DBMS_ERROR_TEXT);
END IF;
http://blog.ebiztechnics.com

13. Summary
• Identify Oracle server features useful
for Form Builder
• Identify PL/SQL8 supported features
• Write PL/SQL code to trap errors raised
by the Oracle server
– Implicit DML
– Explicit DML or stored program units
• Perform DDL with FORMS_DDL
http://blog.ebiztechnics.com