一次一行

Question

已编辑以进一步了解此问题。

我正在尝试从数据库中检索数据并更新单个列。

column1 | column2 | column3 
value1  | value1  | -------
value2  | value2  | -------   <=== this column3 rows does not have value in database yet so it will be blank when I retrieved the data

现在我想通过为其添加值来更新column3行，并使用column3行中的新值将其发送回数据库。

我现在使用的当前代码只能检索并更新单个ID而且我被困在这里。我想要发生的是检索多个ID's并为具有不同值的所有ID's更新相同的列。

以下是我用于检索数据的代码示例

$(document).ready(function(){
        $("#RetrieveList").on('click',function() {
            var status = $('#status').val();
            var date = $('#Date').val();
            var date1 = $('#Date1').val();
            $.post('retrieve.php',{status:status, date:date, date1:date1}, function(data){
            $("#results").html(data);
            });
            return false;
        });

这是PHP代码，

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "sample_db";

// check data before use it and convert from string to expected type, use try, not like here:
$date = $_POST['date'];
$date1 = $_POST['date1'];
// use valid data to select rows
try {
    //1. connect to MySQL database
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);

    //2. set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    //3. create query string (here is answer on your question)
    $sql = 'SELECT column1, column2, column3 FROM sample_table WHERE scheduled_start_date BETWEEN :d1 AND :d2';

    //4. prepare statement from query string
    $stmt = $conn->prepare($sql);

    //5. bind optional parameters
    //if ($status != 'All') $stmt->bindParam(':st', $status);

    //6. bind parameters
    $stmt->bindParam(':d1', $date);
    $stmt->bindParam(':d2', $date1);

    //7. execute statement
    $stmt->execute();

    //8. returns an array containing all of the result set rows 
    $result = $stmt->fetchAll(PDO::FETCH_ASSOC);

    //get count of rows
    $numrow = count($result);

    //print array - there is many solution to print array,
    //to debug you can do: 
    //print_r($result);

} catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
$conn = null;

if($numrow == 0) 
  echo "No results found.";
else 
  echo "Count: $numrow</br>";
{

echo "<table width='auto' cellpadding='1px' cellspacing='0px' border=1 align='center'>
<tr>
<!--<th align='center'><input id=checkall name=checkall id=checkall type=checkbox value='' /></th>-->
<th align='center'><strong>Column1</strong></th>
<th align='center'><strong>Column2</strong></th>
<th align='center'><strong>Column3</strong></th>
</tr>"; 

foreach ($result as $row => $info) {
echo "<form action='crqretrieve_status.php' method='post'>";
echo"<tr>"; 
echo  "<td align='center'>" . $info['column1'] . "<input type=hidden name=column1 value=" . $info['column1'] . " </td>";
echo  "<td align='center'>" . $info['column2'] . "<input type=hidden name=column2 value=" . $info['column2'] . " </td>"; 
echo  "<td align='center'>" . "<input name=column3 value='' </td>";
echo "</tr>"; 
echo "</form>";
}
}
echo "</table>";

?>

从上面的代码中，它有name=column3 value=''，然后我想要分配一个值并将其保存到db。

尝试搜索并且我不确定case将如何有用，因为我的更新将取决于ID's。

以下是我用于单个查询更新的代码，我不知道如何将其与上面的代码相关联。我很感激任何帮助。

// if the 'id' variable is set in the URL, we know that we need to edit a record
if (isset($_GET['id']))
{
// if the form's submit button is clicked, we need to process the form
if (isset($_POST['submit']))
{
// make sure the 'id' in the URL is valid
if (is_numeric($_POST['id']))
{
// get variables from the URL/form
$id = $_POST['id'];
$column1 = $_POST['column1'];
$column2 = htmlentities($_POST['column2'], ENT_QUOTES);
$column3 = htmlentities($_POST['column3'], ENT_QUOTES);
$column4 = htmlentities($_POST['column4'], ENT_QUOTES);

// check that fields are not empty
if ($column1 == '' || $column2 == '' || $column3 == ''|| $column4 == '')
{
// if they are empty, show an error message and display the form
$error = 'ERROR: Please fill in all required fields!';
renderForm($column1, $column2, $column3, $column4, $error, $id);
}
else
{
// if everything is fine, update the record in the database
if ($stmt = $mysqli->prepare("UPDATE sample_table SET column1 = ?, column2 = ?, column3 = ?, column4 = ?
WHERE id=?"))
{
$stmt->bind_param("ssssi", $column1, $column2, $column3, $column4, $id);
$stmt->execute();
$stmt->close();
}
// show an error message if the query has an error
else
{
echo "ERROR: could not prepare SQL statement.";
}

// redirect the user once the form is updated
header("Location: list.php");
}
}
// if the 'id' variable is not valid, show an error message
else
{
echo "Error!";
}
}
// if the form hasn't been submitted yet, get the info from the database and show the form
else
{
// make sure the 'id' value is valid
if (is_numeric($_GET['id']) && $_GET['id'] > 0)
{
// get 'id' from URL
$id = $_GET['id'];

// get the record from the database
if($stmt = $mysqli->prepare("SELECT column1, column2, column3, column4 FROM sample_table WHERE id=?"))
{
$stmt->bind_param("i", $id);
$stmt->execute();

$stmt->bind_result($column1, $column2, $column3, $column4);
$stmt->fetch();

// show the form
renderForm($column1, $column2, $column3, $column4, NULL, $id);

$stmt->close();
}
// show an error if the query has an error
else
{
echo "Error: could not prepare SQL statement";
}
}
// if the 'id' value is not valid, redirect the user back to the view.php page
else
{
header("Location: list.php");
}
}
}

// close the mysqli connection
$mysqli->close();

Answer 1

有几种方法可以做你想做的事：

一次一行

您可以一次更新一行。您可以像以前一样准备查询，但多次调用execute()方法，始终使用不同的值。代码看起来像这样：

$column1Values = array();
$column1Values[42] = "abc";  // key is the id in the database
$column1Values[306] = "def";
// ...

$column2Values = array();
$column2Values[42] = "ghi";
$column2Values[306] = "jkl";
// ...

if ($stmt = $mysqli->prepare("UPDATE sample_table SET column1 = ?, column2 = ? WHERE id=?"))
{
    $stmt->bind_param("ssi", $column1, $column2, $id);
    for ($i=0; $i<count($column1Values); $i++) {
        $column1 = $column1Values[$ids[$i]];
        $column2 = $column2Values[$ids[$i]];
        $id = $ids[$i];
        $stmt->execute();
    }
    $stmt->close();
}

一个更新查询以统治所有

您可以按MySQL update case help所述构建超级查询。但是，动态构建这样的SQL查询可能非常困难，更不用说您必须自己处理SQL注入。

单个列中的行的多次更新

1 个答案:

一次一行

一个更新查询以统治所有