DBI and cursors?

Ruby
1

I’m writing a program to run through large numbers of records in a
database, classify them using a machine learning algorithm (rubysvm),
and
store the results in the database by updating a single column on the
record.

Most of my database work thus far has been using DBI. Is it possible to
update each row through the cursor (similar to how JDBC can be used) in
DBI? Is there some other way of accessing the database that can do this?

–Ken

2

Do you mean reusing a SQL statement to increase performance?

select_sql = ‘select id, class_desc from products’
update_sql = ‘update products SET category = ? where idn = ?’

dbh = DBI.connect(‘dbi:oci8:dbname’, ‘user’,‘passwd’);
select_sth = dbh.prepare(select_sql)
update_sth = dbh.prepare(update_sql)

select_sth.execute
select_sth.each do |row|

3

(Sorry, hit send accidentally before finishing …)

Do you mean reusing a SQL statement/statement handle to increase
performance?

require ‘dbi’

select_sql = ‘select id, class_desc from products’
update_sql = ‘update products SET category = ? where idn = ?’

dbh = DBI.connect(‘dbi:oci8:dbname’, ‘user’,‘passwd’);
select_sth = dbh.prepare(select_sql)
update_sth = dbh.prepare(update_sql)

select_sth.execute
select_sth.each do |row|
category = calculate_category(row[1])
update_sth.execute(row[0], category)
end