db_datareader: The db_datareader role has the ability to run a SELECT statement against any table or view in the database.

db_datawriter: The db_datawriter role has the ability to modify via INSERT, UPDATE, or DELETE data in any table or view in the database.

db_denydatareader: The db_denydatareader role is the exact opposite of the db_datareader role: instead of granting SELECT permissions on any database object, the db_denydatareader denies SELECT permissions.

db_denydatawriter: db_denydatawriter role serves to restrict permissions on a given database. With this role, the user ispreventing from modifying the data on any data via an INSERT, UPDATE, or DELETE statement

db_accessadmin: The db_accessadmin fixed database role is akin to the securityadmin fixed server role: it has the ability to add and remove users to the database.

The db_accessadmin role does not, however, have the ability to create or remove database roles, nor does it have the ability to manage permissions.

Granted with GRANT option: CONNECT

db secuityadmin: The db_securityadmin role has rights to handle all permissions within a database.

The full list is:

DENY, GRANT, REVOKE, sp_addapprole, sp_addgroup, sp_addrole, sp_addrolemember, sp_approlepassword, sp_changegroup, sp_changeobjectowner, sp_dropapprole, sp_dropgroup, sp_droprole, sp_droprolemember The list includes the DENY, GRANT, and REVOKE commands along with all the store procedures for managing roles

. db_ddladmin: A user with the db_ddladmin fixed database role has rights to issue Data Definition Language (DDL) statements in order to CREATE, DROP, or ALTER objects in the database.

db -backpoperator: db_backupoperatorhas rights to create backups of a database. Restore permissions are not granted, but only backups can be performed.

db_owner: Equal to a sysadmin at instance level, DB_OWNER can perform any task at DB Level.

public: By default all the users in database level are granted Public Role