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en:web_development:forms:insert [2022/01/22 04:46]
mag [Switch Statement] 		en:web_development:forms:insert [2023/08/16 09:33] (current)
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                 <legend>Add Hero</legend>                 <legend>Add Hero</legend>
                 <ul>                 <ul>
 +                    <li>
 +                        <label>Hero Alias:</label>
 +                        <input type="text" name="alias" size="30" maxlength="50" hint="Iron Man">
 +                    </li>
                     <li>                     <li>
                         <label>Hero Name:</label>                         <label>Hero Name:</label>
-                        <input type="text" name="name" size="30" maxlength="50">+                        <input type="text" name="identity" size="30" maxlength="50" hint="Tony Stark">
                     </li>                     </li>
                     <li>                     <li>
Line 203: Line 207:
 <code>            if ($rslt->execute($args)) { <code>            if ($rslt->execute($args)) {
  
 +            } else {
 +            
             }</code>             }</code>
   * Add a message in this code block.   * Add a message in this code block.
 <code>            if ($rslt->execute($args)) { <code>            if ($rslt->execute($args)) {
                 $message = "{$_POST['name']} was inserted successfully.";                 $message = "{$_POST['name']} was inserted successfully.";
 +            } else {
 +                $message = "There was a problem inserting {$_POST['name']}.";
             }</code>             }</code>
 +  * The first message will be shown when the query executed successfully.
 +  * The second message will be shown if it wasn't.
  
 ==== Multiple Inserts ==== ==== Multiple Inserts ====
Line 215: Line 225:
  
 ==== Array Push ==== ==== Array Push ====
-  * Let's leave the query for last.+  * Let's leave the query for last because we will need to filter out already existing appearances.
   * First let's build our array of arguments - a pair for each movie.   * First let's build our array of arguments - a pair for each movie.
   * Each pair of arguments is the name of our hero and the name of the movie, which we can do in a <html>foreach</html> loop.   * Each pair of arguments is the name of our hero and the name of the movie, which we can do in a <html>foreach</html> loop.
 <code>            foreach($_POST['movie'] as $movie) { <code>            foreach($_POST['movie'] as $movie) {
  
-            }<code>+            }</code>
   * And we can add them to an existing array using the <html>array_push</html> function.   * And we can add them to an existing array using the <html>array_push</html> function.
 <code>                        array_push($args, $_POST['hero'], $movie);</code> <code>                        array_push($args, $_POST['hero'], $movie);</code>
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                     $margs  = array($_POST['hero'], $movie);                     $margs  = array($_POST['hero'], $movie);
                     $rslt  = $pdo->prepare($mquery);                     $rslt  = $pdo->prepare($mquery);
-                    if (!$rslt->execute($margs)) {+                    $rslt->execute($margs); 
 +                    if (!$row = $rslt->fetch()) {
                         array_push($args, $_POST['hero'], $movie);                         array_push($args, $_POST['hero'], $movie);
                     }</code>                     }</code>
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   * $mquery is the query asking whether the hero / movie pair already exists.   * $mquery is the query asking whether the hero / movie pair already exists.
   * $margs is the array of parameters for the query.   * $margs is the array of parameters for the query.
-  * We then run the query and if it doesn't exist (<html>if (!$rslt->execute($margs))</html>) then we add it to the list of arguments. +  * We then run the query and if it doesn't exist (<html>if (!$row = $rslt->fetch())</html>) then we add it to the list of arguments. 
-  * What if it's a new movie?+  * What if it's a new movie? We don't want to add the word 'new' as the movie title. We need to change it to <html>$_POST['new_movie']</html> instead.
   * Let's check using an 'if statement'.   * Let's check using an 'if statement'.
 <code>                if ($movie == 'new') { <code>                if ($movie == 'new') {
Line 258: Line 269:
 ==== Count ==== ==== Count ====
   * We could have created the query first and added pieces in the loop, but there is a more elegant way.   * We could have created the query first and added pieces in the loop, but there is a more elegant way.
-  * If we know how many movies have been added, we can simply add the right number of <html>(?,?) at the end of the query.+  * If we know how many movies have been added, we can simply add the right number of <html>(?,?)</html> at the end of the query.
   * We can get the number of elements in the <html>$args</html> array using <html>count</html> and then halve it.   * We can get the number of elements in the <html>$args</html> array using <html>count</html> and then halve it.
   * <html>count</html> is like <html>.length</html> in Javascript, counting the number of elements in an array.   * <html>count</html> is like <html>.length</html> in Javascript, counting the number of elements in an array.
Line 265: Line 276:
  
 ==== Repeating String ==== ==== Repeating String ====
-  * We then need to add exactly that many copies of <html>(?,?) at the end of the query, but they need to be separated by a <html> , </html>.+  * We then need to add exactly that many copies of <html>(?,?)</html> at the end of the query, but they need to be separated by a <html> , </html>.
 <code>            $values = str_repeat('(?,?), ', $movies-1) . '(?,?)';</code> <code>            $values = str_repeat('(?,?), ', $movies-1) . '(?,?)';</code>
   * This technique uses a function called <html>str_repeat</html> to repeat a set string a number of times. If we repeated '(?,?),' the correct number of times, we'd have a hanging <html> , </html> at the end which would cause an error. Instead, we add one less  than the required amount (<html>count($movies) -1</html>), then add <html>(?,?)</html> at the end.   * This technique uses a function called <html>str_repeat</html> to repeat a set string a number of times. If we repeated '(?,?),' the correct number of times, we'd have a hanging <html> , </html> at the end which would cause an error. Instead, we add one less  than the required amount (<html>count($movies) -1</html>), then add <html>(?,?)</html> at the end.
   * Now, our query is:   * Now, our query is:
-<code>            $query = "INSERT INTO heroes ('character_name', 'movie') VALUES $values";</code>+<code>            $query = "INSERT INTO heroes ('alias', 'movie') VALUES $values";</code>
   * Before we run our query, we should check that code works, that both query and arguments look as they should.   * Before we run our query, we should check that code works, that both query and arguments look as they should.
   * Add the following before <html>break</html>.   * Add the following before <html>break</html>.
Line 276: Line 287:
   * Choose a hero and select a number of movies including the new one. Enter a movie that isn't already in our list anywhere and click 'Add Appearance'.   * Choose a hero and select a number of movies including the new one. Enter a movie that isn't already in our list anywhere and click 'Add Appearance'.
   * Now check the error logs in Putty.   * Now check the error logs in Putty.
-  * +  * If the query and arguments array look good, it's time to send them to the database. 
 +<code> 
 +                $rslt  = $pdo->prepare($query); 
 +                if ($rslt->execute($args)) { 
 +                    $message = "$movies appearances were inserted successfully."; 
 +                } else { 
 +                    $message = "There was a problem inserting $movies appearances."; 
 +                }</code> 
 +  * This code also includes the check to see if the query was successful and adds an appropriate message in either case. 
 +  * Save and upload your code, then open 'form.php' and submit some new appearances to check that everything works. 
 +  * The one problem we still have is that if the user only adds movies that are already in the database, we're creating a query and trying to submit it with no values. 
 +  * Let's fix that by stopping if there are no new movies to add. 
 +<code>            if ($movies > 0) { 
 +                $values = str_repeat('(?,?), ', $movies-1) . '(?,?)'; 
 +                $query = "INSERT INTO appearances (alias, movie) VALUES $values"; 
 +                error_log("MURRAY: $query    " . print_r($args, 1)); 
 +                $rslt  = $pdo->prepare($query); 
 +                if ($rslt->execute($args)) { 
 +                    $message = "$movies appearances were inserted successfully."; 
 +                } else { 
 +                    $message = "There was a problem inserting $movies appearances."; 
 +                } 
 +            } else { 
 +                $checked = count($_POST['movie']); 
 +                $message = "All $checked appearances are already in the database."; 
 +            }</code> 
 +  * Rather than referring to <html>$movies</html>, which will be 0 in this case, I've changed the message to refer to the original number of movies submitted and stating that they were all already in the database. 
 +  * This has been a big activity, but there's more to do in the next activity. 
 + 
 +[[en:web_development:forms:update|Next: UPDATE Queries]]
en/web_development/forms/insert.1642855579.txt.gz · Last modified: 2023/08/16 09:33 (external edit)

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