Class to handle connections in the database

Some time ago I created the class below to do CRUD operations on the database.

Based on good programming practices, what would you change in class? and why?

<?php        
    Banco::getConexao();

    abstract class Banco {
        private static $database = 'mysql';
        private static $host = 'localhost';
        private static $banconome = 'testes';
        private static $user = 'root';
        private static $pass = '';
        private static $conexao = NULL;

        public function __construct() { }

        public function __destruct(){
            self::$conexao = NULL;
        }// __destruct

        public static function getConexao(){
            $dsn = self::$database.':host='.self::$host.';dbname='.self::$banconome;
            try{
                if(is_null(self::$conexao)):
                    self::$conexao = new PDO($dsn, self::$user, self::$pass);
                    self::$conexao->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
                endif;
                return self::$conexao;
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }   
        }// getConexao

        public static function insert($tabela, $dados){
            $sql = 'INSERT INTO '.$tabela.' (';
            foreach($dados as $key => $value):
                $campos[] = $key;
                $tokens[] = '?';
                $valores[] = $value;
            endforeach;
            try{
                $sql .= implode(', ', $campos).') VALUES ('.implode(', ', $tokens).')';
                $query = self::$conexao->prepare($sql);
                $query->execute($valores);
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// insert

        public static function selectAll($tabela, $condicao = NULL){
            $sql = 'SELECT * FROM '.$tabela;
            if(!is_null($condicao)) $sql .= ' WHERE '.$condicao;
            try{
                $query = self::$conexao->prepare($sql);
                $query->execute();
                return $query->fetchAll(PDO::FETCH_OBJ);
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// selectAll

        public static function select($tabela, $campos, $condicao = NULL){
            $sql = 'SELECT '.$campos.' FROM '.$tabela;
            if(!is_null($condicao)) $sql .= ' WHERE '.$condicao;
            try{
                $query = self::$conexao->prepare($sql);
                $query->execute();
                echo $sql;
                return $query->fetchAll(PDO::FETCH_OBJ);
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// select

        public static function update($tabela, $dados, $condicao = NULL){
            $sql = 'UPDATE '.$tabela.' SET ';
            foreach($dados as $key => $value):
                $campos[] = $key.'=?';
                $valores[] = $value;
            endforeach;
            $sql .= implode(', ', $campos);
            if(!is_null($condicao)) $sql .= ' WHERE '.$condicao;
            try{
                $query = self::$conexao->prepare($sql);
                $query->execute($valores);
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// update

        public static function delete($tabela, $condicao = NULL){
            $sql = 'DELETE FROM '.$tabela;
            if(!is_null($condicao)) $sql .= ' WHERE '.$condicao;
            try{
                $query = self::$conexao->prepare($sql);
                $query->execute();
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// delete

        public static function countResult($tabela, $campo = NULL){
            !is_null($campo) ? $campo = $campo : $campo = '*';
            $sql = 'SELECT '.$campo.' FROM '.$tabela;
            try{
                $query = self::$conexao->prepare($sql);
                $query->execute();
                echo $sql;
                return count($res = $query->fetchAll(PDO::FETCH_OBJ));
            }catch(PDOException $e){
                self::erroLog(__FILE__, __FUNCTION__, $e->getMessage());
            }
        }// countResult

        public static function erroLog($arquivo, $rotina, $mensagem){
            echo 'Aconteceu um erro com os seguintes Dados:<br />';
            echo '<b>No Arquivo = </b>'.$arquivo.'<br />';
            echo '<b>Na rotina = </b>'.$rotina.'<br />';
            echo '<b>Mensagem = </b>'.$mensagem.'<br />';
        }// erroLog

    }// Banco
?>

How the class is used:

$dados = array('nome' => 'Teste', 'senha' => '123');

$dados2 = array('nome' => 'Teste2', 'senha' => '1234');

$res = Banco::select('user', 'nome');

$res = Banco::selectAll('user', "nome LIKE '%teste%'");

$res = Banco::select('user', 'nome=Teste, senha=123');