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4GL's virtues (Part 2) Intergration with SQL

4GL makes code that would be difficult to write purely in SQL easy ,
plus it adds extra capabilities that would not be possible.

The following is a select loop that retrieves the result set
of a SQL query row by row and then manipulates it inside the loop.
Inside the loop you are free to use more SQL queries or 4GL code or mix them both!

For example, you can test conditions using if..then..else statements, assign values to host variables, load a tablefield or update tables in the database!


select h_c_ylik = c_ylik,
h_no_seir = no_seir,
h_ps = ps,
h_sxolia = sxolia
from mlax
where end_axr='Ο'
{
if h_no_seir = '' then
update mlax m
set ps = ps + :h_ps
where end_axr = '' and
no_seir = '' and
c_ylik = :h_c_ylik;
inquire_ingres (h_rowcount = rowcount,
h_errorno=errorno);
if h_errorno!=0 then
rollback;
callframe err_handler;
endif;
if h_rowcount = 0 then
insert into mlax
(c_ylik,no_seir,end_axr,ps,sxolia)
values
(:h_c_ylik,'','',:h_ps,:h_sxolia);
inquire_ingres (h_rowcount = rowcount,
h_errorno=errorno);
if h_errorno!=0 then
rollback;
callframe err_handler;
endif;
endif;
else
insert into mlaxr
(c_ylik,no_seir,end_axr,ps,sxolia)
values
(:h_c_ylik,:h_no_seir,'',:h_ps,:h_sxolia);
inquire_ingres (h_rowcount = rowcount,
h_errorno=errorno);
if h_errorno!=0 then
rollback;
callframe err_handler;
endif;
endif;
};






There are many situations like this that make evident that 4GL is a rapid development tool

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