Let's say you have an existing database at your organization. Included here may be lists of products, customers etc and you want this data to be available on your forms in the field. Our Select question is the ideal place to store this kind of data in your form. You can have thousands of entries in this field type without degrading performance or the user experience. Large lists are automatically made searchable too. Inputting all of this information would be impractical, but you can import it via a CSV file.
Depending on the database you use and how you are able to interface with it, you should be able to export one or more tables into MS Excel format. Easier yet may be to use Excel's data sources functionality to connect directly to the database, providing you have valid credentials. Once in Excel, arrange the columns so that you have the customer/product name in the first column, followed by the unique identifier or customer/product code on to the right of that:
Bob's Ball Bearings BOB234
Now, use Excel export menu to save this data as a comma-separate file. You're looking for something with a format like this:
Bob's Ball Bearings,BOB234
With this file in hand (you may want to verify the export worked fine by viewing the file in a text editor), add a select question to your form. Click on Options and then towards the bottom of the dialog, click the "Import CSV List" button. Upload you file (it may take a while) and you should be good to go.
We hope this tip serves as a good starting point. If you have specific databases you are trying to get data out of, please post below so others can share their experiences.