14.3 ADD_COLUMN Procedure

This procedure adds a column to the columns collection. Columns collections can be passed the OPEN_*_CONTEXT calls in order to request only a subset of columns. This is particularly useful for web sources where no SQL statement is involved. If no or an empty column array is passed, all columns defined in the web source are being fetched.

Syntax

procedure add_column(
    p_columns         in out nocopy t_columns,
    p_column_name     in            varchar2,
    p_data_type       in            t_data_type default null,
    p_sql_expression  in            varchar2    default null );

Parameters

Example

declare
    l_columns     apex_exec.t_columns;
    l_context     apex_exec.t_context;
begin
    apex_exec.add_column(
        p_columns     => l_columns,
        p_column_name => 'ENAME' );

    apex_exec.add_column(
        p_columns     => l_columns,
        p_column_name => 'SAL' );

    l_context := apex_exec.open_web_source_query(
        p_module_static_id => '{web source module static ID}', 
        p_columns          => l_columns
        p_max_rows         => 1000 );

        while apex_exec.next_row( l_context ) loop
           -- process rows here ...
        end loop;

    apex_exec.close( l_context );
exception
    when others then
         apex_exec.close( l_context );
         raise;    
end;