Use PL/SQL procedure to guard against malformed CSV files before upload

Question

Hi all,
In my CSV upload utility, I've implemented error checking procedures, but they are invoked only AFTER data has been uploaded to temp table. This doesn't catch the following sample scenarios:
1. The CSV is malformed, with some rows shifted due to fields and separators missing here and there.
2. User has chosen a wrong CSV to upload (most likely number of fields mismatch)
I'm wondering if it is a good idea to have procedure to read in the CSV, scan each line, count the number of fields (null fields but with delimiters showing the field exist is ok) for each record. If every single record matches the required number of fields for that table, then the CSV is ok, and the insert from external table to temp table is allow. This will ensure at least the CSV file has a valid matrix size for the target table, but rest of error checking is left until after temp table is populated.
One of my concerns is, I specify "missing field values are null" in the external table parameters, which is necessary since not all fields are required. Does this specification causes a row with missing trailing separators still considered valid? If so then the stored procedure must be programmed to omit such a case.
What do you think? Many thanks.

Answer 1

Hi, Cuauhtemoc Amox
Thank you for your advice. I have set web adi  using PL SQL interface.
I have decided to go futher
i have a procedure like that
procedure delete_old_data ( p_id in number, p_description in varchar2)
as
begin
               begin
               if g_flag ='N' then
               delete from xx_test;
                g_flag='Y';
                else null;
                end if;
                end;
insert into xx_test (p_id,p_descriptiom);
end;
G_FLAG is a global variable with default value ='N'  in my package. When web_adi upload
first row from excel sheet, then procedure delete all data from table and change g_flag to 'Y'.
All other rows uploads succesfully; it  works fine.
But when user change data in excel sheet and try to upload second time. DELETE_OLD_DATA procedure doesnt work in proper way.
I have found what problem is. when user use same template and try to upload data several times there is same SESSION_ID in database.
i.e. g_flag ='Y' when user try to upload second time. But when user log off and create template again it is work properly.
My question is: How i can different upload attempts? May be there is some id for each upload proccess.
if i can use this ID in my procedure user will have opportunity to use same template.
Thank you