Databases Reference
In-Depth Information
Every updatable column in a Tabular Form will have a unique ID in a sequential order (the SQL
statement) mapped to one of these arrays:
f01 0001 … f01 n
The limit of 50 arrays is a major constraint with Tabular Forms. Currently, a Tabular Form will allow
users to update or create a maximum of 50 columns per page. The maximum number of columns an
Oracle table can have is 1024. Thus, you can find yourself in a position where a table has more columns
than you can display on a page.
You will receive the same error if you try building manual Tabular Forms and index a column
outside of the specified range. The error is similar to the error you get if you try to create a simple form
with more than 100 items per page, as shown in Figure 3-1.
Figure 3-1.
Typical error message after referencing a nonexisting array
Caution
Keep in mind that new item types available in APEX 4 (Simple Checkbox and Popup Key LOV) will
require two of these IDs. Therefore, the limitation of 50 updatable columns per page may vary depending on how
many of those elements you have.
Purpose of Tabular Forms
The main purpose of a Tabular Form can be described in two cases:
•
To maintain smaller sets of data
•
To maintain parent/child relations
A typical example of the first case would be a page in your application where you maintain lists of
values. Normally a list of values will contain a couple of records (options), and you could display this set
of data on one page. The reason for choosing this method is so that you can quickly edit and save
records without having to drill down, paginate, or switch between the pages.
An example of the second case would be an application for order management. An order would be a
parent record (master) and ordered items would be child records (detail). In most cases, there is a
limited (small) amount of details for one master record. Normally you would want to maintain that
relation between the master and the detail on one page. In that case, Tabular Forms are the way to go.
You can even use Tabular Forms to update thousands of records with up to 50 columns each. In that
case, however, you will face several issues:
