-No Condition -

The Default.  This will cause the component to always be rendered.

Exists (SQL query returns at least one row.

This is very common for use when it is desirable to only display a component if a record exists in the database.  A common use would be for verifying the user is an administrator.

NOT Exists (SQL query returns no rows)

This is the reverse of the previous item.  If a row were to be returned by the query, it would result in a FALSE answer and the component would not be rendered.

SQL Expression

This is similar to the WHERE clause in an SQL statement. 

A good use for this is when none of the other condition types meets your need.  For example: you may want to have a condition that the page must be equal to 101 and it is not in print friendly mode.  This is similar to having two conditions work together to return a true of false value.

Request = Expression1

This condition type is mostly used during page processing on conditions, validations, and processes.  For example, a computation does not have a condition where you can specify the button from a select list.  So, for computations you would have to use this type of a condition.

Value of Item in expression 1 Is NULL

This type of condition is commonly used on buttons such as a Create or Insert.  Let’s say you have a page item on a form named P100_CUSTOMER_ID.  If that page item is NULL then it would indicate this is a new customer and you would want the Create or Insert buttons to be rendered.  This is exactly how the HTML DB wizards setup a form created by a wizard.

Value of Item in expression 1 Is NOT NULL

This type of condition is commonly used on buttons such as a Update or Delete.  Let’s say you have a page item on a form named P100_CUSTOMER_ID.  If the page item has a value then the customer already exists and you would want the Update and Delete buttons to be rendered.  This is exactly how the HTML DB wizards setup a form created by a wizard.

Current Page Is Contained Within Expression 1

For this condition you provide a comma delimited list of application page IDs.  This type of condition would be used to display Lists or Tabs only for a select list of pages.

Current page is NOT in Printer Friendly Mode

This condition type is often used on the application page referred to as Page 0 (zero).  It is common to display a banner at the top of the page using an after header region.  You would use this condition to prevent the region from being rendered when the user put it into the Printer Friendly mode.

User is Authenticated

In the event there is a page that is public and does not require authentication.  However, that page is also used by authenticated users.  You have one region on the page that you only want to be displayed if the user is authenticated while the rest of the regions can display in either condition.  For that one region you could use this type of condition.  I’ve used this type of region on a page so I could see auditing information, but it would not be displayed to the public.

Never

This will prevent the component from being rendered.  It’s also used to prevent a branch, computation, validation, or process from being executed.  I’ve most often used this computation to prevent certain processes from running while I test an application page.