You need a login to access the ePO database (Windows or SQL user):
The account used to upgradeePolicy Orchestrator must have rights to:
•Create a new database, set permissions on tables and stored procedures, and create SQL Jobs.
•Modify, Delete, Rename, Create, Use, Read, Write, Change Permissions, on any, and/or all, Tables, Stored Procedures, Columns, Rows, Fields, Views on the Master, TempDB, MSDB, and ePO Database.
These abilities are given to these roles:
•SQL administrator (SA)
In the windows SQL server you don't need access.
Patch upgrades invariably need to make changes to the db as described above to resolve issues addressed in the patch, hence the requirement.