Overlapping User and Group Permissions (Master Data Services)
Applies to: 
SQL Server - Windows only
Azure SQL Managed Instance
A user's permissions are based on:
Permissions from group memberships.
Permissions assigned explicitly to the user.
If a user is a member of multiple groups, and those groups have access to Master Data Manager, the following rules apply:
Deny overrides all other permissions. If the object permission is Deny in one group, the effective permission is deny.
Access permission is a union all effective permissions on a group. If the object permission is Create from one group and Update from other group, the effective permission is Create and Update.
These rules apply to both the Models and Hierarchy Members tabs. Permissions are resolved for each tab and then combined. For more information, see How Permissions Are Determined (Master Data Services).
Note
You can view the resolution of user and group overlapping permissions in the user interface. Both the Models and Hierarchy Members tab have a drop-down list from which you can choose Effective to view effective permissions.
Example 1
The user belongs to Group 1 and Group 2.
The user has Read permission to the Product entity.
Group 1 has Update permission to the Product entity.
Group 2 has Read permission to the Product entity.
Result: The user's effective permission is Update to the Product entity.
Example 2
The user belongs to Group 1 and Group 2.
The user has Read permission to the Product entity.
Group 1 has Update permission to Product entity.
Group 2 has Deny permission to the Product entity.
Result: The user's effective permission is Deny to the Product entity.
Example 3
The user belongs to Group 1 and Group 2.
The user has Update permission to a group of members in a hierarchy node.
Group 1 has Read permission to a group of members in a hierarchy node.
Group 2 has Read permission to a group of members in a hierarchy node.
Result: The user's effective permission is Update to the members.
See Also
How Permissions Are Determined (Master Data Services)
Overlapping Model and Member Permissions (Master Data Services)