Demonstrate Net.data built-in reporting functions

DTW_TB_DUMPH

This built-in function relies on the data in a Net.data %TABLE variable which are closely related to SQL result sets.
The Net.Data %TABLE variable used in this example is generated by populating it from the result of an SQL SQLECT statement.
Click here to show an explanation of this mechanism.

Figure 1.

The result set of an SQL SELECT statement within a DTW_SQL function block can be returned by Net.data into a %TABLE variable. A %TABLE variable is simply a matrix of rows and columns, analogous to a spreadsheet.

However, a %TABLE variable must first be defined before it can be used. This is done by defining the variable within a %DEFINE block at the start of the source code. A %DEFINE block is in some way analogous to the variable declarations that would appear at the start of a CL program. To define a variable named mytable as a Net.data %TABLE variable the following %DEFINE block would be placed at the start of the source.

%define {           
  mytable = %TABLE  
%}

To populate a %TABLE variable with the result set from an SQL statement all that is required is to pass the variable name as an input/output parameter to the DTW_SQL function as in the following example -

%function(dtw_sql) list(inout mytable) {    
  SELECT CUSNUM, LSTNAM, INIT, STREET, CITY 
  FROM QIWS/QCUSTCDT WHERE CDTDUE > 0       
  %report { %row { %} %}                    
%}

Notice that the DTW_SQL function has a %REPORT block that does nothing. The effect is that it does not generate any output and therefore only returns the SQL result in the %TABLE variable passed as an inout parameter.

The DTW_TB_DUMPH function renders a Net.data %TABLE variable one ROW at a time within a <PRE> tag

The complete source for this example can be viewed at dtw_tb_dumph.

This example first runs a DTW_SQL function named @list() which selects records from the file QIWS/QCUSTCDT.
Function @list() does nothing other than return a %TABLE variable named mytable.
The built-in function DTW_TB_DUMPH is then passed %TABLE mytable.
So there are just 2 lines within the %HTML block as follows -

@list(mytable)                                        
@dtw_tb_dumph(mytable)

CUSNUM   LSTNAM    INIT   STREET          CITY     
938485   Johnson   J A    3 Alpine Way    Helen    
389572   Stevens   K L    208 Snow Pass   Denver   
475938   Doe       J W    59 Archer Rd    Sutter   
192837   Lee       F L    5963 Oak St     Hector

Notice that the column headings for the table have been automatically populated with the corresponding database field name.