"Stored Procedures are evil", "Stored Procedures do break database independency", "Do not use Stored Procedure in my enterprise".
This are some of words I hear about SPs. But you can do simple loads of data quickly.
With Stored Procedures, you can load big data quickly, (and make very fast systems also).
I will use PostgreSQL, which is a DB I can use for this.
Let's see a file...
0000023ABRAAO 09081985
0000045JOSEPH 10071997
...
The format table is:
create table employee (
ID NUMER(7)
NAME CHAR(100)
HIRE_DATE DATE --(MMDDYYYY) in file
);
A log table is:
create table log_errors (
id bigserial,
table_name varchar(100),
error_date timestamp,
line text,
message varchar(200),
constraint log_errors_pk primary key(id)
);
A staging table for the file (we'll COPY file into this):
create table temp_employee
file_line text,
id bigserial,
constraint tepk primery key(id)
);
Let's divide the SP in parts.
Part 1: Header.
CREATE OR REPLACE FUNCTION load_employees()
RETURNS boolean AS
$BODY$declare
line text;
emp employee%ROWTYPE;
begin
Part 2: Loading the data to the real table. We'll make it by the complex way: update or insert and log the bad records into
log_errors.
f
or line in select file_line from temp_employee order by id
loop begin
emp:=null;
emp.name:=trim(substr(line,9, 100));
emp.hire_date:=to_date(substr(line,110, 8), 'MMDDYYYY');
emp.id:=substr(line, 1, 8);
update employee set
name = emp.name,
hire_date = emp.hire_date
where id = emp.id;
if not found then
insert into employee(id, name, hire_date) values
(emp.id, emp.name, emp.hire_date);
end if;
exception
when others then
insert into log_erros (table_name, error_date, line, message)
values ('employee', now(), line, 'Error');
end;
end loop;
Part 3: Cleaning records from temp_employee.
delete from temp_employee;
Part 4: SP Footer.
return true;
end;$BODY$
LANGUAGE plpgsql VOLATILE
Part 5: Call the function from
psql.
bash-4.2$ cat /tmp/employee.txt|psql -h thehost db -c "copy temp_employee from stdin;select load_employees()"
If you need to run it automatically, remember to put the "Part 5" in the
crond service. For Windows server, use the Task Scheduler.