I have 5 websites about auto sales in 5 different languages: French, Bulgarian, English, Italian, Spanish. The db structure is the same to all, what do you recommend me to do: 1. keep one common data base ? 2. keep 5 different databases ?
You should keep one database for all sites. But language dependent data may go into different columns/tables but in one database. Keeping a single database reduce redundant data and hassle to backup/maintain.