I'm getting the following error when attempting to delete data from a table:

Here is the coachSchedule table which is where I'm attempting to delete data from:

This is the table that its conflicting with:

Is there way that i can delete data from the coach schedule table without getting the error above?
Below is my current query:
private void button2_Click(object sender, EventArgs e)
{
try
{
string query = "DELETE cs from coachSchedule cs where coachScheduleId= @coachScheduleId";
cmd = new SqlCommand(query, _isqlDataFunctions.GetConnection());
cmd.Parameters.AddWithValue("@coachScheduleId", scheduleId);
_isqlDataFunctions.ManagingData(cmd, "Coach schedule has been deleted.");
clearFields();
DisplayAllSchedules();
button1.Enabled = false;
button2.Enabled = false;
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}


