Naming tables and columns: best practices?

[eluser]Ciaro[/eluser]
Hi there.

I was wondering, how do you guys name your tables and columns (fields) in MySQL/MSSQL?

I've been doing some googling, but there are just too many different approaches. I'm yet to figure out a consequent way that suits me best.

Should I use id or tablename_id as primary key? What about foreign keys? Singular or plural table names? Short or long table names? tablename_fieldx or just fieldx?

I currently already have made up my mind about following things:

'lowercase' all the way
underscores above CamelCase

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Thanks.