system/Database/SQLite3/Forge.php
public function dropDatabase(string $db_name): bool
	{
		// In SQLite, a database is dropped when we delete a file
		if (! is_file($db_name))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('Unable to drop the specified database.');
			}

			return false;
		}

		// We need to close the pseudo-connection first
		$this->db->close();
		if (! @unlink($db_name))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('Unable to drop the specified database.');
			}

			return false;
		}

		if (! empty($this->db->dataCache['db_names']))
		{
			$key = array_search(strtolower($db_name), array_map('strtolower', $this->db->dataCache['db_names']), true);
			if ($key !== false)
			{
				unset($this->db->dataCache['db_names'][$key]);
			}
		}

		return true;
	}
public function dropDatabase(string $db_name): bool
	{
		// In SQLite, a database is dropped when we delete a file
		if (! is_file($db_name))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('Unable to drop the specified database.');
			}

			return false;
		}

		// We need to close the pseudo-connection first
		$this->db->close();
		if (! @unlink($db_name))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('Unable to drop the specified database.');
			}

			return false;
		}

		if (! empty($this->db->dataCache['db_names']))
		{
			$key = array_search(strtolower($db_name), array_map('strtolower', $this->db->dataCache['db_names']), true);
			if ($key !== false)
			{
				unset($this->db->dataCache['db_names'][$key]);
			}
		}

		return true;
	}
Drop database

@param string $db_name

@return boolean
@throws \CodeIgniter\Database\Exceptions\DatabaseException