I know i've had to do a similar thing to this before now - for a large number of users - but I had to do this manually.

Yes, I'm sure it wouldn't be impossible to do - although as Skenow says above, one of the biggest problems would be to avoid conflicting entries - ie checking that the username doesnt' already exist.

That however isn't impossible to check.

If it helps it will be ok even if we username is same as emailid

Hi, did you manage to work this out, or would you still like us to figure out a solution for this problem?

I am still looking for a solution... It would be great if you could provide a solution or push me in the right direction.

skenow had an idea for that using the formulize module. I've asked him if he could have a look.

Formulize did also work with another module created by FreeFormSolutions called RegCodes. At the time it was created, Formulize did not support import/export as well as it does now. You can use the import/export in Formulize to update data in Formulize, but it is not intended for use on the system users' table.

The RegCodes module included some changes to core files to allow Formulize to handle the registration process. Those changed files have undergone some extensive changes since the last release of RegCodes, so it wouldn't be feasible to use them directly anymore.

If all your content was contained within Formulize, I would point you in that direction. But, that doesn't appear to be the case. Formulize can read system tables, but is not designed to update system tables. And, you will need to update at least 2 different system tables - the groups_users_link table and the users table. If you use the Profile module, there will be another table with the custom fields to update, too.

Tell me more about your business model - do you think the updates will need to be done in bulk, or since they are submitting forms by mail it might be sufficient to have your office person update the system through the web? Could the participants submit any information online instead of by paper registration?

The updates will need to be made in bulk. Also participants fill up the form in writing, which is then sent to office staff who converts it to excel, sends it to me and I upload it to the website to update their details.

The data sheet for level 1 will add participants and their details to the website as profiles.
Then after level 2 another data sheet is uploaded which updates the details of existing members. Important fields in the form which will change in each update is user group and certificate no. (A custom profile field) for the level (course) the participant has completed.

Participants will not be allowed to change / update their certificate no. and groups them belong to. These fields are updated only by admin.

Can this be achieved?

I don't think you need a module, just a script that can read a .csv file and update the database (which should not be stored on the server). Either way, you will need to carefully sanitise and escape the data before inserting it. Passwords will need to be created for user accounts as well.

I still think it would be better to train your staff to do data entry directly into the web interface though, using the existing create user/custom profile module functionality. The Excel sheet is an unnecessary step that complicates things IMHO and can always be exported from the database if you really need it.

Or if you are ok with command line MySQL, you could try importing the Excel file directly via .csv. I would suggest experimenting with it locally first though and having a good time series of backups.

This also looks interesting (NB, I have not tried it).