Customer database is an organized record of all your customer data – contact details, orders, communication, activity on site, etc. It automatically tracks and processes customer behavior to make it actionable for marketing. In a customer database, you can explore individual customer behavior, preferably systematized session by session.
It also lets you filter customers by traits and actions to reach a certain segment. If it enables you to contact them directly from the same platform, it is an ecommerce CRM.