Oracle Database Tips by Donald Burleson

Examining the Results of the Tabular Form Wizard in APEX

The Form Wizard creates a report region, some buttons, some processes, and a branch.

·         Report Region:  In the regions section, a Report region has been created.  Tabular Forms are really reports with editable fields.

·         Buttons:  Four buttons were created by the wizard.  The cancel button is a simple redirect, which means it will not execute page processes.  The other three buttons, Multi-Row Delete, Submit, and Add, are used in the conditional processing of the automatic row processes.  More about the buttons will be included later in the Examining Tabular Form Buttons section.

·         Processes:  The Automatic Row processes were explained in the section on Forms.  Tabular forms have something similar called Multi Row processes.  There are three processes that work on Tabular Forms: Multi Row Update, Multi Row Delete, and the Add Rows to Tabular Form process.  These processes dynamically build the SQL statements for updating the data in the database table.

Examining Tabular Form Buttons

There is something special about the Tabular Form MULTI_ROW_DELETE button.  The others simply submit the page and the processes use the REQUEST in the conditional processing.  However, the MULTI_ROW_DELETE button has the Optional URL Redirect set to confirm with the user they really want to perform the delete action.  The URL Target attribute is set to the following.

javascript:confirmDelete(htmldb_delete_message,'MULTI_ROW_DELETE');

The confirmDelete function asks the user if they really want to delete data.  If they answer yes, the page is submitted and the REQUEST is set to MULTI_ROW_DELETE.  The ApplyMRD process on the page has the conditional processing set to respond to this REQUEST.

Examining the Multi Row Processes

There are two Multi Row processes: Multi Row Update (MRU) and Multi Row Delete (MRD).  Their names explain the function they perform.  These processes write dynamic SQL statements to update the database from the Tabular Form.  When these processes are used, they are set to execute On Submit - After Computations and Validations. 

The MRU and MRD processes have the same attributes.  The most important section is the Source section shown in Figure 8.14.  The attributes are explained here:

·         Table Owner:  The schema name for the owner of the table.

·         Table Name:  Enter the table name or view.  MRD's and MRU's can only dynamically build SQL statements for a single table or view.

·         Primary Key Column:  This is the first column of the primary key for the table.  It is used for building the WHERE clause for the dynamic statement.

·         Second Key Column:  This is the column name for the second database column making up the primary key for the table.  The MRU and MRD processes can only be used for tables that have two or fewer columns making up the primary key. 

The above book excerpt is from:

Easy HTML-DB Oracle Application Express

Create Dynamic Web Pages with OAE

ISBN 0-9761573-1-4   

Michael Cunningham & Kent Crotty

http://www.rampant-books.com/book_2005_2_html_db.htm