Wednesday, May 11, 2011

Oracle Forms Interview Questions & Answers Part 1


Oracle Forms – Technical – Interview – Question Answers

What are the Various Master and Detail Relation ships.
The various Master and Detail Relationship are
a) NonIsolated = The Master cannot be deleted when a child is existing
b) Isolated = The Master can be deleted when the child is existing
c) Cascading = The child gets deleted when the Master is deleted.

What are the master-detail triggers?
On-heck_delete_master
On_clear_details
On_populate_details These are automatically created when you create Master-Details block.

What are the types of Blocks in Forms?
Base Table block  - based on database table/views
Control Block  - non-database items are placed here like Calculation values,buttons,checkbox etc.

What are the Various Block Coordination Properties
The various Block Coordination Properties are
a) Immediate
Default Setting. The Detail records are shown when the Master Record are shown.
b) Deffered with Auto Query
Oracle Forms defer fetching the detail records until the operator navigates to the detail block.
c) Deffered with No Auto Query
The operator must navigate to the detail block and explicitly execute a query


Can a property clause itself be based on a property clause?
Yes


What are the different windows events activated at runtimes?
When_window_activated
When_window_closed
When_window_deactivated
When_window_resized
Within this triggers, you can examine the built in system variable system. event_window to determine the name of the window for which the trigger fired.

What are the trigger associated with image items?
When-image-activated fires when the operators double clicks on an image itemwhen-image-pressed fires when an operator clicks or double clicks on an image item


What is trigger associated with the timer?
When-timer-expired.

What is the difference between CALL_FORM, NEW_FORM and OPEN_FORM?
CALL_FORM: start a new form and pass control to it. The parent form will be suspended until the called form is terminated.
NEW_FORM: terminate the current form and replace it with the indicated new form. The old form's resources (like cursors and locks) will be released.
OPEN_FORM: Opens the indicated new form without suspending or replacing the parent form.

When a form is invoked with call_form, Does oracle forms issues
a save point?
Yes


What is new_form built-in?
When one form invokes another form by executing new_form oracle form exits the first form and releases its memory before loading the new form calling new form completely replace the first with the second. If there are changes pending in the first form, the operator will be prompted to save them before the new form is loaded.

What are visual attributes?
Visual attributes are the font, color, pattern proprieties that you set for form and menu objects that appear in your application interface.


Can one issue DDL statements from Forms?
DDL (Data Definition Language) commands like CREATE, DROP and ALTER are not directly supported from Forms because your Forms are not suppose to manipulate the database structure.
A statement like CREATE TABLE X (A DATE); will result in error:
Encountered the symbol "CREATE" which is a reserved word.
However, you can use the FORMS_DDL built-in to execute DDL statements. Eg:
FORMS_DDL('CREATE TABLE X (A DATE)');

Can one execute dynamic SQL from Forms?
Yes, use the FORMS_DDL built-in or call the DBMS_SQL database package from Forms. Eg:
FORMS_DDL('INSERT INTO X VALUES (' || col_list || ')');
Just note that FORMS_DDL will force an implicit COMMIT and may de-synchronize the Oracle Forms COMMIT mechanism.

What is the difference between the following statements?
Form A:   Insert into emp(ename) values ('MK Maran');
Form B:  FORMS_DDL('insert into emp(ename) values('||''MK Maran')');

User have to commit the form manually for Form A
Once the Form B statement executes, it will be implicitly commited.


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