[SQL] PostgreSQL Function

[Rehan Saleem]

hi 
i want to create a function in postgresql that take input for columns from user 
for example first_name , last_name, addres. and will put them into table , and 
i also want to use exception if user enters wrong data. will some one help me 
how can i create thats function , because i am new to postgresql . i know how 
to do it in MS-SQL , i also have that code .if you dont understand what am 
trying to say . i can post sql code .thanks