問題描述

比如說，我們要在一個表中插入多行:

Say, we have multiple rows to be inserted in a table:

$rows = [(1,2,3), (4,5,6), (7,8,9) ... ] //[ array of values ];

使用 PDO:

$sql = "insert into `table_name` (col1, col2, col3) values (?, ?, ?)" ;

現在，您應該如何繼續插入行?像這樣嗎?

Now, how should you proceed in inserting the rows? Like this?

$stmt = $db->prepare($sql);

foreach($rows as $row){
  $stmt->execute($row);
}

或者，像這樣?

$sql = "insert into `table_name` (col1, col2, col3) values ";
$sql .= //not sure the best way to concatenate all the values, use implode?
$db->prepare($sql)->execute();

哪種方式會更快更安全?插入多行的最佳方法是什么?

Which way would be faster and safer? What is the best way to insert multiple rows?

推薦答案

您至少有以下兩個選擇:

You have at least these two options:

$rows = [(1,2,3), (4,5,6), (7,8,9) ... ];

$sql = "insert into `table_name` (col1, col2, col3) values (?,?,?)";

$stmt = $db->prepare($sql);

foreach($rows as $row)
{
    $stmt->execute($row);
}

OR:

$rows = [(1,2,3), (4,5,6), (7,8,9) ... ];

$sql = "insert into `table_name` (col1, col2, col3) values ";

$paramArray = array();

$sqlArray = array();

foreach($rows as $row)
{
    $sqlArray[] = '(' . implode(',', array_fill(0, count($row), '?')) . ')';

    foreach($row as $element)
    {
        $paramArray[] = $element;
    }
}

// $sqlArray will look like: ["(?,?,?)", "(?,?,?)", ... ]

// Your $paramArray will basically be a flattened version of $rows.

$sql .= implode(',', $sqlArray);

$stmt = $db->prepare($sql);

$stmt->execute($paramArray);

正如你所看到的，第一個版本有很多簡單的代碼；但是第二個版本確實執行批量插入.批量插入應該更快，但我同意 @BillKarwin 在絕大多數實現中不會注意到性能差異.

As you can see the first version features a lot simpler code; however the second version does execute a batch insert. The batch insert should be faster, but I agree with @BillKarwin that the performance difference will not be noticed in the vast majority of implementations.

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