!IsPostack submitting data to SQL with .net c# application

Hello,
I'm trying to understand !IsPostback.
Should I be using if(!IsPostBack) after a button click before submitting data to a SQL database like the following?

 protected void btn101_Click(object sender, EventArgs e)
{     
       if (!IsPostBack)
            {
           //insert into statement
            }
}

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Could this help prevent duplicate data entries which I have seen occasionally?

Thank you!