After searching the net and trying a couple of different plugins for importing users to WordPress I decided that I would have to build one myself. Although some of the plugins worked well they did not meet the requirements that my situation required.
- I needed to keep the primary key ID from the previous user database, for that was used to link table data.
- I had data in a custom field which I added to the end of the wp_users table that also needed to be imported.
When importing users you need to create entries in both the wp_users table and the wp_usermeta tables.
How importing users was done.
- I created a .csv file from the old user db to import into WordPress. users.csv
- Created a php script to read the .csv file and insert the data into both the user tables. import.php