Hi there!

I'm quite a newbie to E/R notaions and therefore I have the following questions:

1. In Microsoft Visio one can choose from two symbol-sets: IDEF1X and Relational....

I don't quite understand when to use the Relational-set because I can't see that it gives any information about the cardinality (min, max) constraints with the notation of arrows. I have seen a tutorial where one first use the Relational symbolset (arrows) and then fine-tune with crow feet (IDEF1X-notation)...is this what the Relational-symbolset is for - to make rough sketches?

2. How is the constraints symbolised with chicken/crowfeets and so on implemented in the database? f.i in a MySql-database?

3. what is the difference between crow-feet and chicken-feet?

Thanks in advance!