hello guys. i want to ask some questions about SQL constraints when importing data in odoo

let's say i have 1 field (name) and I've added SQL constraints unique to that field.. what happens if we importing 2 rows with the same name?

for example:
rows 1: test123
rows 2: test123

do the validation sql constraints pop up shows or we keep importing the data but only the last row (row 2)? thanks