I decided to switch my OSCommerce 2.3.3 store to a different URL. Instead of using 2.3.3 again in the new site, I decided to use 2.3.4 (the official version, not the Responsive/BootStrap version).
1. I installed my 2.3.4 store on my new URL. (Recommendation: don't change your username and password from those in your old store, since they are stored in the database.) In order to complete that installation, I used MySQL to created a new database which I called oscommerce234.
2. I logged into the admin of my 2.3.3 store and created a backup of my old database. Then I used FTP to download it to my home computer. Then I renamed it as backup233.sql and I used FTP to upload it to the backup directory (oscommerce-2.3.4/catalog/admin/backups) of my new store.
3. I downloaded the add-on which provides a .sql file for upgrading databases from 2.2MS2 to 2.3.3 (http://addons.oscommerce.com/info/8731). It has been kept current and now includes the codes for upgrading from 2.3.3 to 2.3.4. (It does not, however, include the commands for upgrading to 2.3.4 Responsive/BootStrap.)
4. On my home computer I edited that upgrade file using my text editor (Notepad++). I only kept the commands for moving from 2.3.3 to 2.3.4. Then I saved the file with the name 233_to_234.sql and uploaded it using FTP to the backup directory (oscommerce-2.3.4/catalog/admin/backups) of my new store. Here are the comments (lines that start with #) and commands that were in that file:
#Increase column size
alter table sessions modify sesskey varchar(128) not null;
#Adds "Administration Tool -> Configuration -> Shipping/Packaging -> Allow Orders Not Matching Defined Shipping Zones"
insert into configuration (configuration_title, configuration_key, configuration_value, configuration_description, configuration_group_id, sort_order, set_function, date_added) values ('Allow Orders Not Matching Defined Shipping Zones ', 'SHIPPING_ALLOW_UNDEFINED_ZONES', 'False', 'Should orders be allowed to shipping addresses not matching defined shipping module shipping zones?', '7', '5', 'tep_cfg_select_option(array(\'True\', \'False\'), ', now());
5. Then I used Putty to log into the website of my new store. I logged into MySQL. Then at the MySQL prompts (mysql>) I created a new database which I called oscommerce233 and then I upgraded it by uploaded my backup233.sql file into it and then my 233_to_234.sql file into it. (Note that /var/www/html is the absolute path to my oscommerce-2.3.4 store; your absolute path will be different.)
mysql> CREATE DATABASE oscommerce233;
mysql> use oscommerce233;
mysql> source /var/www/html/oscommerce-2.3.4/catalog/admin/backups/backup233.sql;
mysql> source /var/www/html/oscommerce-2.3.4/catalog/admin/backups/233_to_234.sql;
6. Then I used FTP to download the two configure.php files (catalog/includes/configure.php and catalog/admin/includes/configure.php). I edited each of them using my text editor (notepad++) changing database references from oscommerce234 to oscommerce233. Then I uploaded both configure.php files back to the website. As a result, the following statement now appears in those configuration files:
That's all there was to it. It seems that everything is working, but I won't know for sure until I get my store operational. If this doesn't work out, I can change the database references in those configuration files back to the way they were before (oscommerce234 instead of oscommerce233), and I'll be using the oscommerce234 database that was created when first setting up the oscommerce 2.3.4 store.