Database cannot be resolved to a variable

There was an Error in the creating of Database there was an error was

indicating the word "Database" and it will displayed "Database cannot be

resolved a variable". So please tell me how to rectify it....

package com.flocater;
import com.flocator.R;
import android.app.Activity;
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class AddFriends extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.addfriends);
    }

    public void addFriend(View v) {
        // get access to views
        EditText editName = (EditText) this.findViewById(R.id.editName1);
        EditText editPhone = (EditText) this.findViewById(R.id.editPhone1);
        EditText editArea = (EditText) this.findViewById(R.id.editArea1);
        EditText editCity = (EditText) this.findViewById(R.id.editCity1);

        try {
            DBHelper dbhelper = new DBHelper(this);
            SQLiteDatabase db = dbhelper.getWritableDatabase();
            Log.d("Account", "Got Writable database");
            // execute insert command

            ContentValues values = new ContentValues();
            values.put(Database.FRIENDS_NAME, editName.getText().toString());
            values.put(Database.FRIENDS_PHONE, editPhone.getText().toString());// "The error was displayed in the word Database"
            values.put(Database.FRIENDS_AREA, editArea.getText().toString());
            values.put(Database.FRIENDS_CITY, editCity.getText().toString());

            long rows = db.insert(Database.FRIENDS_TABLE_NAME, null, values);
            db.close();
            if (rows > 0) {
                Toast.makeText(this, "Added Friend Successfully!",
                        Toast.LENGTH_LONG).show();
                this.finish();
            } else
                Toast.makeText(this, "Sorry! Could not add Friend!",
                        Toast.LENGTH_LONG).show();

        } catch (Exception ex) {
            Toast.makeText(this, ex.getMessage(), Toast.LENGTH_LONG).show();//print message
        }

    }``
}