How to avoid Multiple Inserts in the database

Question

Ola would like to know how I can use php to avoid adding the same item to a database on a save page that adds the names of the subcategories if you update your browser.

Since I cannot use in the database Unique in the table subcategory in the name field because it would make it impossible for me to use the same name if it is affiliated to another category.

Below are the two tables.

Table Category

CREATE TABLE IF NOT EXISTS `categoria` (
  `id` int(255) NOT NULL AUTO_INCREMENT,
  `categoria_url` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `nome` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `modo` enum('UNICO','MULTIPLO') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'UNICO',
  `data` date NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `categoriaUnica` (`categoria_url`),
  UNIQUE KEY `nomeUnico` (`nome`),
  KEY `colunasIndexadas` (`id`,`categoria_url`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;

Table subcategory

CREATE TABLE IF NOT EXISTS `subcategoria` (
  `id` int(255) NOT NULL AUTO_INCREMENT,
  `categoria_url` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `subcategoria_url` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `temporada` int(3) NOT NULL,
  `nome` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `cat` int(255) NOT NULL,
  `semana` enum('Selecionar Semana','Domingo','Segunda-Feira','Terca-Feira','Quarta-Feira','Quinta-Feira','Sexta-Feira','Sábado') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'Selecionar Semana',
  `ativadorOn` enum('ON','OFF') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'OFF',
  `sinopse` text COLLATE utf8_unicode_ci NOT NULL,
  `status` enum('Completo','Incompleto','Andamento','Pausado','Lançamento') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'Andamento',
  `genero` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `genero_url` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `numeroMedias` int(255) NOT NULL DEFAULT '0',
  `autor` char(20) COLLATE utf8_unicode_ci NOT NULL,
  `acessos` int(255) NOT NULL,
  `arquivo_nome` varchar(355) COLLATE utf8_unicode_ci NOT NULL,
  `arquivo_tipo` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
  `arquivo_data_cad` date NOT NULL,
  `arquivo_hora_cad` time NOT NULL,
  PRIMARY KEY (`id`),
  KEY `colunasIndexadas` (`id`,`cat`,`categoria_url`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;

Answer 1

In the Unique Key function, you can put as many fields as you want to keep in the table, the row as being Única

Example with more than one field

UNIQUE KEY `nomeIdUnique` (`nome`,`cat`)

On your table

CREATE TABLE `subcategoria` (
  `id` int(255) NOT NULL AUTO_INCREMENT,
  `categoria_url` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `subcategoria_url` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `temporada` int(3) NOT NULL,
  `nome` char(255) COLLATE utf8_unicode_ci NOT NULL,
  `cat` int(255) NOT NULL,
  `semana` enum('Selecionar Semana','Domingo','Segunda-Feira','Terca-Feira','Quarta-Feira','Quinta-Feira','Sexta-Feira','Sábado') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'Selecionar Semana',
  `ativadorOn` enum('ON','OFF') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'OFF',
  `sinopse` text COLLATE utf8_unicode_ci NOT NULL,
  `status` enum('Completo','Incompleto','Andamento','Pausado','Lançamento') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'Andamento',
  `genero` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `genero_url` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `numeroMedias` int(255) NOT NULL DEFAULT '0',
  `autor` char(20) COLLATE utf8_unicode_ci NOT NULL,
  `acessos` int(255) NOT NULL,
  `arquivo_nome` varchar(355) COLLATE utf8_unicode_ci NOT NULL,
  `arquivo_tipo` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
  `arquivo_data_cad` date NOT NULL,
  `arquivo_hora_cad` time NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `nomeIdUnique` (`nome`,`cat`),
  KEY `colunasIndexadas` (`id`,`cat`,`categoria_url`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

This way it will never repeat itself, and if you are using PDO, you do not need to send the error to the log file

try {

} catch (PDOException $e) {
    if ($e->getCode !== 23000) {
        //log
    }
}

Answer 2

1. You can use access tokens.
2. a 1 and 2 pages must have session_start(); at the beginning and pass a token with a randomly generated number or code, making it impossible to access the page again without going to 1 page!
3. A 1 page and where the user ve adds things to the cart (by exeplo" on the 2 page where the add process occurs in the database!

How to generate the token in 1 page?

<?php
session_start();
function geraToken()
{
return rand(1, 1000)."".rand(1, 1000); // Gerar numeros aleatorios
}
$_SESSION['token'] = geraToken();
?>

How to use token on 2 page?

<?php
session_start();
if(!isset($_SESSION['token']))
{
    die("Acesso negado!");
}
//Adicione aki o resto da 2 pagina...
//...

// NO fim do processo adicione isto
$_SESSION['token'] = ""; // Fazendo a token invalida e impedindo o refresh da pagina!
?>