How should I best name my timestamp fields?

You should describe the purpose of the column and not necessarily the data type. You can include date/time/timestamp in the name, but you should also include the meaning. For example

• CreationDate
• StartDate
• StatusTime
• Accessed
• Updated

Adding Date/Time/Timestamp and such at the end is particularly useful when the abscence of the addition would conflict with another column. For example, a table may need both a Status and a StatusTime.

How about xyz_at for a timestamp and xyz_on for a date field - eg start_at or start_on?

Normally I'd avoid including the data type in the field name - much better if you can infer what you need to know about the type from the name of any field (a field called description is unlikely to be an integer) - but being able to tell the difference between a timestamp and a date is often helpful.

I use:

• created_at
• updated_at