create(), delete(), describeSObjects(), query(), retrieve()
SELECT Id, PermissionSetId FROM PermissionSetAssignment WHERE AssigneeId = '005600000017cKt'
SELECT Id, AssigneeId FROM PermissionSetAssignment WHERE PermissionSetId = '0PS30000000000e'
SELECT Id, ProfileId FROM User WHERE Id = '005D0000001GMAT'
SELECT Id, LicenseId FROM PermissionSet WHERE Id = '0PS30000000000e'
SELECT Id, Assignee.Name, PermissionSet.Name FROM PermissionSetAssignment WHERE PermissionSet.LicenseId = null