What are record groups ? * Can record groups created at run-time?

What are record groups ? * Can record groups created at run-time? 

A record group is an internal Oracle Forms data structure that has a column/row framework similar to a database table. However, unlike database tables, record groups are separate objects that belong to the form module in which they are defined. A record group can have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE provided that the total number of columns does not exceed 64K. Record group column names cannot exceed 30 characters.
Programmatically, record groups can be used whenever the functionality offered by a two-dimensional array of multiple data types is desirable.
TYPES OF RECORD GROUP:
Query Record Group A query record group is a record group that has an associated SELECT statement. The columns in a query record group derive their default names, data types, and lengths from the database columns referenced in the SELECT statement. The records in a query record group are the rows retrieved by the query associated with that record group.
Non-query Record Group A non-query record group is a group that does not have an associated query, but whose structure and values can be modified programmatically at runtime.
Static Record Group A static record group is not associated with a query; rather, you define its structure and row values at design time, and they remain fixed at runtime.

What are ALERT? 
An ALERT is a modal window that displays a message notifying operator of some application condition.

Can a button have icon and label at the same time ? 
-NO

What is mouse navigate property of button? 
When Mouse Navigate is True (the default), Oracle Forms performs standard navigation to move the focus to the item when the operator activates the item with the mouse.
When Mouse Navigate is set to False, Oracle Forms does not perform navigation (and the resulting validation) to move to the item when an operator activates the item with the mouse.

What is FORMS_MDI_WINDOW? 
forms run inside the MDI application window. This property is useful for calling a form from another one.

What are timers ? when when-timer-expired does not fire? 
The When-Timer-Expired trigger can not fire during trigger, navigation, or transaction processing.

Can object group have a block? 
Yes , object group can have block as well as program units.

How many types of canvases are there. 
There are 2 types of canvases called as Content and Stack Canvas. Content canvas is the default and the one that is used mostly for giving the base effect. Its like a plate on which we add items and stacked canvas is used for giving 3 dimensional effect.

What are user-exits? 
It invokes 3GL programs.