how to process?

Hi,

I am new to sql processing.  I have a java connection to my database and
will be inserting to a table with a primary key, which will provide
uniquness to the rows in my table.  In java, I will be handling exceptions
and I am assuming postgresql would throw an SQLException if a user tried to
add a record with a key that already exists.

First, I want to know if that is a good assmption.  Second, and my real
question, should I gard against this by doing a select on the key and seeing
if it already exists?  Or should I just handle this as one of the exceptions
that might occur?

Please point me to reading if this is an area of discussion that I should
research further.

Thanks in advance.

Sam Deel
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