Oracle Forms Questions

1. How do you control the constraints in forms? 

This can be done by selecting the Use Constrain Property to ON.

2.When will ON-VALIDATE-FIELD trigger executed? 

ON-VALIDATE-FIELD triggers are used for field validation. It fires when the field validation status is New or changed. However, if the field status is already valid then any further change to the value in the field will not fire this trigger.

3. What is the difference between system.current_field and system.cursor_field? 

The only difference between these two is that System.current_field gives name of the field and System.cursor_field gives name of the field with block name.

4. What are dynamic reports? How will you create them? 

Following steps should be followed to build a Dynamic Report:

Create a temporary table first.
Then insert data to the temporary table using the After Form Trigger.
Generate the report using this temporary table in the Data Model.
Delete all records from the temporary table in the After Report trigger.

5. Difference between Oracle Forms and Apps Forms.

Oracle Forms

Oracle Forms renders applications using metadata stored in an .fmx file.
It runs client-side PL/SQL.
It is accessed using a web browser and its user interface is rendered using a JVM.
It uses exact positioning.
It provides robust field-level validation and event processing.
It uses BI Beans as its integrated charting engine.
It supports a range of locking models with pessimistic as the default.
Each connected user in It maintains a synchronous connection to the Oracle database.
It uses synchronous connections to allow transactions to span multiple screen interactions.
With Oracle Forms, Application logic is processed in the Oracle database, a mid-tier Forms Server, or in the rich client.

Apps Forms

It renders applications using metadata stored in an Oracle database.
It uses server-side PL/SQL.
It is also invoked from a Web browser but its user interface is HTML and JavaScript.
It uses HTML-relative positioning.
It supports declarative page-level validation and event processing. Programmatic field-level validation and event processing requires Javascript and AJAX.
It uses Flash Charts as its integrated charting engine.
Due to its asynchronous architecture, It uses an optimistic locking model.
It does not transparently allow transactions to span page views. It programmatically supports transactions spanning page views using collections.
Its users are asynchronously connected to the Oracle database.
With Apps Forms, PL/SQL application logic is processed within the Oracle database. Client-side logic is implemented using JavaScript. HTTP communications are facilitated using Apache and Mod/PLSQL.

6. Sequence of firing triggers in forms. 

The following sequence should be used to fire triggers when a form opens:

1. Pre-Form
2. Pre-Block
3. Pre-Record
4. Pre-Text-Item
5. When-New-Form-Instance
6. When-New-Block-Instance
7. When-New-Record-Instance
8. When-New-Item-Instance

The folowing sequence should be followed when you exit from the form:

1. post text item
2. post record
3. post block
4. post form

7. What is a record Group? What are different types of record group? 

A record group is an oracle forms data structure that has a column/row framework similar to a database table.

There are three types of record groups: query record groups, non-query record groups, and static record groups.

Query record group
A query record group is a record group that has an associated SELECT statement. Query record groups can be created and modified at design time or at runtime.

Non-query record group
A non-query record group is a group that does not have an associated query. Non-query record groups can be created and modified only at runtime.

Static record group
A static record group is not associated with a query. Static record groups can be created and modified only at design time.

8. What is a trace file and how is it created? 

The files that are created when an oracle background process encounters an exception are Trace files.

Processes like dbwr, lgwr, pmon, smon create them.

Trace files are also created by ORA-00600 error or due to some diagnostic dump events

9. Can a single canvas have multiple windows ? 
ANs. NO, In a window we have more than one canvas .