Hi,
I am trying to use hibernate3 framework. I want to make sure that i can migrate my application between different relational databases. What care should i take during design and coding phase so that the migration is smooth.

Hi,
that's not very hard.
just avoid writing native SQL queries, but always make use of Hibernate's HQL or criterias to make sure you can switch the dialect. Otherwise make sure your SQL is really standard and cross-database compatible.
Also avoid using special primary key identifiers which are supported only by some databases (e.g. if you select "sequence", the model will work only on databases supporting sequences, while if you leave it to "auto" Hibernate will use sequences where they are supported or switch to other means).