Contains one row for each SQL Server user mapped to a user (or with an alias) of the current database. When a user tries to access a database, SQL Server looks for a valid uid entry in sysusers. If one is not found, it looks in sysalternates.suid. If the user's suid is found there, the user is treated as the database user whose suid is listed in sysalternates.altsuid.
| Column | Datatype | Description |
|---|---|---|
| suid | smallint | Server user ID of the user being mapped. |
| altsuid | smallint | Server user ID of the user to whom another user is mapped. |
sysalternates clustered, unique on suid
| sp_addalias | sp_dropalias | sp_dropuser |
| sp_adduser | sp_droplogin | sp_helpuser |
| sp_changedbowner |