Without seeing the code for your block as it is currently it's very hard to point you in the direction of what namespaces you'll need to use and what functions you'll need to use.

Sorry for not providing enough information. Here is the controller for a simple block: (Not sure I need the btName and btDescription) edit.php has two inputs: destination_code and destination_name

<?php
namespace Concrete\Block\HikingDestination;

use Concrete\Core\Block\BlockController;
use Page;
use Core;
use Database;

class Controller extends BlockController
{
protected $btTable = 'btHikingDestination';
protected $btName = 'Hiking Destination';
protected $btDescription = 'Hiking Destination Pages';
protected $btInterfaceWidth = "600";
protected $btInterfaceHeight = "450";

public function getBlockTypeDescription()
{
return "Enter a hiking destination state (region if intl) code and name to access the regiondata table and display the hiking destination page for the state/region.";
}

public function getBlockTypeName()
{
return "Hiking Destination";
}

public function getSearchableContent()
{
$content = array();
$content[] = $this->destination_code;
$content[] = $this->destination_name;
return implode(' - ', $content);
}

public function view() {

/* Retrieve data from the main RegionData table */

$destination_key = trim($this->destination_code);

$db = \Database::connection();
$results = $db->fetchColumn('SELECT region_code,region_name,region_order,country_code,state_code,short_desc,latitude,longitude,zoom FROM RegionData WHERE state_code = ? ORDER BY region_order', [$destination_key])

/* Get the data for each region within the state */
$this->set('regioncount' , $results->RecordCount());
$i = 1;
while($row=$results->fetchrow())
{
$this->set("region_code{$i}", $row['region_code']);
$this->set("region_name{$i}", $row['region_name']);
$this->set("region_order{$i}", $row['region_order']);
$this->set("country_code{$i}", $row['country_code']);
$this->set("state_code{$i}", $row['state_code']);
$this->set("short_desc{$i}", $row['short_desc']);
$this->set("latitude{$i}", $row['latitude']);
$this->set("longitude{$i}", $row['longitude']);
$this->set("zoom{$i}", $row['zoom']);
++$i;
}
}

public function edit() {
}

public function save($args)
{
parent::save($args);
}
}
?>

Sorry -- working too fast --

Corrected two syntax errors:
Should be Application\Block\HikingDestination not Concrete\Block\HikingDestination

Added a semicolon after the $results = $db->fetchColumn .... line

Also have all the database code wrong because of the new DBAL doctrine. See corrected View function (below), although I am still having problems viewing the data in the rows. Probably more mistakes in how I am fetching the data from the rows.

public function view() {

/* Retrieve data from the main RegionData table */

$destination_key = trim($this->destination_code);

$db = \Database::connection();
$sql = "SELECT region_code,region_name,region_order,country_code,state_code,short_desc,latitude,longitude,zoom FROM RegionData WHERE state_code = ? ORDER BY region_order";
$results = $db->prepare($sql);
$results->bindValue(1, $destination_key);
$results->execute();

/* Get the data for each region within the state */
$this->set('regioncount' , $results->rowCount());
$i = 1;
while($row=$results->fetch())
{
$this->set("region_code{$i}", $row['region_code']);
$this->set("region_name{$i}", $row['region_name']);
$this->set("region_order{$i}", $row['region_order']);
$this->set("country_code{$i}", $row['country_code']);
$this->set("state_code{$i}", $row['state_code']);
$this->set("short_desc{$i}", $row['short_desc']);
$this->set("latitude{$i}", $row['latitude']);
$this->set("longitude{$i}", $row['longitude']);
$this->set("zoom{$i}", $row['zoom']);
++$i;
}
}