Checking if the data is already exist in the database

I have to check if the data is already exist in the database before inseting the new data. I have tried to check if the name is already exist or not but i got an error.so please can you help?

CountryBLL.getCountryByCountryName(countryName).Rows(0).IsNull(0)

Checking to see if data already exists in database table

I am assuming you allow the user to enter a country name in a text box. Then you need to check a database table that contains a column that includes all of the country names entered thus far. You can get the value entered by the user then loop through the database table and compare the text box value to the row column value. If the values match you can exit the loop using the break statements and display a message to the user telling them that the country already exists in the database.

Something like this.
foreach(DataRow row in datatable)
{
if(textbox1.Text == row["country"].ToString())
{
lblInfo.Text = "Record already exists in the database";
break;
}
}