The first job of any in DBA when he starts his new position is to make sure the backups are getting done. You can be guaranteed that if something goes wrong and a restore is required. The first person they will look to, and quite rightly so, is the DBA.
It surprises me how many large and critical databases have been set up by developers but nothing has been done about the backup strategy
I have come across systems at very large multinational before where a little knowledge has verged on incompetence. In that case the client had a system that had no daily full backups but was managing to do a transaction log backup every hour! This scenario had gone on for months!
So in short your daily full backups are your starting point of any restore. If you require a restore to a point in time between these backups you should apply the intervening transaction log backups in order. Commonly the setup is a daily full backup and hourly transaction log backups.
I don’t believe that there is a DBA out there that will fit the mould of a perfect DBA. Every client you work for will have different preconceptions as to what a DBA is. They may be looking for someone with a sys admin slant on things. They may be looking for someone who knows SQL inside out. They may also be looking for someone who lives and breathes the internals of the RDBMS.
On the whole I think a DBA should be experienced in all aspects but with the proviso that if they don’t know they should have the knowledge and intelligence to be able to adapt and find out. If you ask a lawyer a specific question of law, they may not know the answer straight away. They will however know where to look to find out!