Monday, September 3, 2012

Restrictions and enhancements in Oracle APEX 4.1

 Configuration Requirements

The value of the character set portion of PlsqlNLSLanguage in the configuration of the mod_plsql Database Access Descriptor (DAD) must be set to AL32UTF8, regardless of the underlying database character set.

New Checkbox Plug-in Attribute Type

The new plugin has been added to the apex 4.1 version , where the select list is listed with the check box beside it . 

New Region SQL Statement Column Plug-in Attribute Type

With the new Region SQL Statement Column custom plug-in attribute (only available for region type plug-ins), plug-in developers can create more flexible region type plug-ins which are based on an SQL statement (plug-in configuration has checked Region Source is SQL Statement in Standard Attributes). This new custom plug-in attribute type will show the column names of the SQL statement specified in the region source.
An example is a region type plug-in which displays a chart. To populate the chart a developer has to specify an SQL statement in the region source. In 4.0 the plug-in developer would have to exactly specify how many columns the SQL statement has to have and which column position is mapped to which feature. For example an SQL statement format could look like:
select label,
  from table
As you can see in the above example, only label and value are required. All the other columns are optional. When using this chart type plug-in, you first have to know the format of the SQL statement and you have to write odd SQL statements if, for example, you want to have a statement where only the labelvalue and tooltip is set. Such a statement would look like:
select label,
       null as link,
       null as color,
  from mytable
The above SQL looks odd and gets more complicated if the SQL statement provides even more options.
In 4.1, the SQL statement specified in the region source is greatly simplified and the plug-in developer can now make implementation of the plug-in much more declarative for the average developer who is using the plug-in. The plug-in developer would define five new custom plug-in attributes of type Region SQL Statement Column. These would, for example, be called Label Column, Value Column, Link Column, Color Column and Tooltip Column. Only Label Column and Value Column are required.
If a developer is using the chart plug-in, in 4.1 the developer can now just enter the following into the Region Source:
select *
  from my_table
select dname,
       sum(sal) as total_sal,
       'Total Employees: '||count(employee_id) as total_employees
  from my_table
The developer is then prompted to actually map the different columns of the SQL statement to the Label Column, Value Column, Link Column, Color Column and Tooltip Column custom attributes of the plug-in. In our example, the developer would enter dname for the Label Column, total_sal for Value Column and total_employees for Tooltip Column. This is much more declarative, because the developer doesn't have to know how the SQL statement is formatted. This also makes it a lot easier if columns are optional.

Application Attributes to Control Browser Security

1)   In Application Express 4.1,
        there are two new application attributes to control Browser Security: 
        1)Cache  -- to save page content  on the disk and memory of the browser . 
         2) Embed in Frames.. browser is allowed to display your application's pages within a frame. 

 "SET_COMPATIBILITY_MODE Procedure" in the Oracle Application Express API Reference.