• db_accessadmin – Granted: ALTER ANY USER, CREATE SCHEMA, Granted with Grant option – Connect
• db_backupoperator – Granted: BACKUP DATABASE, BACKUP LOG, CHECKPOINT
• db_datareader – Granted – SELECT
• db_datawriter – Granted – INSERT, UPDATE and DELETE
• db_ddladmin – Granted – Any DDL operation
• db_denydatareader – Denied – SELECT
• db_denydatawriter – Denied – INSERT, UPDATE and DELETE
• db_owner – Granted with GRANT option: CONTROL
• db_securityadmin – Granted: ALTER ANY APPLICATION ROLE, ALTER ANY ROLE, CREATE SCHEMA, VIEW DEFINITION
• dbm_monitor – Granted: VIEW most recent status in Database Mirroring Monitor
• sp_helprolemember : List out the members MAPPED with the server ROLES

Note:

Fixed database roles are not equivalent to their database-level permission. For example, the db_owner fixed database role has the CONTROL DATABASE permission. But granting the CONTROL DATABASE permission does not make a user a member of the db_owner fixed database role.

Note:

Fixed database roles are not equivalent to their database-level permission. For example, the db_owner fixed database role has the CONTROL DATABASE permission. But granting the CONTROL DATABASE permission does not make a user a member of the db_owner fixed database role.