To collect information from an offline inventory database, you will need to use “Data Import.” This capability allows joining records generated by offline systems with the data collected by Google Analytics. This gives you a more comprehensive view of your business data to analyze it and make data-driven decisions.
For example, suppose you are a publisher. In that case, you can join hits from Google Analytics and data dimensions from your CRM system to see the relative contributions of different authors to your web resource.
Note that the Data Import feature allows you to import the following types of data:
- Hit data. You can import hit data directly into Analytics to avoid tracking code, the Mobile SDKs, Collection API, or the Measurement Protocol.
- Extended data. You can extend the information already collected and processed with a user, campaign, geographical, content, product, and custom data.
- Summary data. You can use summary data import to sum the uploaded metrics.
Google Analytics cannot collect data from which systems by default? – https://support.google.com/analytics/answer/3191589?hl=en