嵌套的Foreach循环占用了太多时间 - Nested Foreach loop taking too much time

Nested Foreach loop taking too much time

本文关键字：太多时间 Foreach 循环嵌套 | 更新日期: 2023-09-27

我正在使用Nested Foreach循环将数据存储在mysql中。但它需要太多的处理时间。如何减少最长执行时间。

foreach ($results as $r) {
    mysqli_query($con,"insert into commercial values('".mysqli_real_escape_string($con,$r['MST_MLS_NUMBER'])."')");
    $val=1;
    $objects = $rets->GetObject('Property', 'Photo', $r['MST_MLS_NUMBER'], '*', 0);
    foreach ($objects as $pho) {
        mysqli_query($con,"insert into cmtval values('".mysqli_real_escape_string($con,$r['MST_MLS_NUMBER'])."')");
    }
}

您应该使用批量插入

INSERT INTO tbl_name (a,b,c) VALUES(1,2,3),(4,5,6),(7,8,9);

通过foreach循环，您应该首先执行查询，然后使用mysqli_query执行查询。

$query1 = "insert into commercial values ";
$query2 = "insert into cmtval values ";
foreach ($results as $r)
{
     $query1 .= "('" . mysqli_real_escape_string( $con, $r['MST_MLS_NUMBER']) . "'), ";
     $val=1;
$objects = $rets->GetObject('Property', 'Photo', $r['MST_MLS_NUMBER'], '*', 0);
  foreach ($objects as $pho)
  {
     $query2 .= "('" . mysqli_real_escape_string( $con, $r['MST_MLS_NUMBER']) . "'), ";
  }
}
mysqli_query($con, $query1);
mysqli_query($con, $query2);

我还没有测试代码。测试一下，如果有什么遗漏，请告诉我。批量更新减少了一些时间。

此外，如果在单个查询中在数据库中保存了太多数据，并且索引太多，则插入数据需要时间。

您可以制作这样的

foreach ($results as $r)
{
  mysqli_query($con,"insert into commercial values('".mysqli_real_escape_string($con,$r['MST_MLS_NUMBER'])."')");
    $val=1;
    $objects = $rets->GetObject('Property', 'Photo', $r['MST_MLS_NUMBER'], '*', 0);

    // generate partial query strings for insert multiple records
    $numbers=array();
    foreach ($objects as $pho)
    {
        $numbers[]= "('".mysqli_real_escape_string($con,$pho['MST_MLS_NUMBER'])."')";
    }
    mysqli_query($con,"insert into cmtval values".implode(",",$numbers)); // it will insert multiple record 
}

您可以使用prepare语句并使用不同的值执行以插入

例如

// prepare and bind
$stmt = $conn->prepare("INSERT INTO MyGuests (firstname, lastname, email) VALUES (?, ?, ?)");
$stmt->bind_param("sss", $firstname, $lastname, $email);
// set parameters and execute
$firstname = "John";
$lastname = "Doe";
$email = "john@example.com";
$stmt->execute();
$firstname = "Mary";
$lastname = "Moe";
$email = "mary@example.com";
$stmt->execute();
$firstname = "Julie";
$lastname = "Dooley";
$email = "julie@example.com";
$stmt->execute();

设置参数和执行行应该在foreach循环中

编制报表和绑定参数准备好的语句是一种用于高效地重复执行相同（或类似）SQL语句的功能。

准备好的报表基本上是这样工作的：
准备：创建一个SQL语句模板并将其发送到数据库某些值未指定，称为参数（标有"？"）。示例：INSERT INTO MyGuests VALUES（？，？，？）数据库对SQL进行解析、编译和查询优化语句模板，并在不执行结果的情况下存储结果执行：稍后，应用程序将值绑定到参数，数据库执行该语句。应用程序可以使用不同的值