I have in a text database field a json encoded chart configuration in the form of:

我在文本数据库字段中有一个json编码的图表配置，其形式为：

{"Name":[[1,1],[1,2],[2,1]],"Name2":[[3,2]]}

The first number of these IDs is a primary key of another table. I'd like to remove those entries with a trigger when the row is deleted, a plperl function would be good except it does not preserve the order of the hash and the order is important in this project. What can I do (without changing the format of the json encoded config)? Note: the chart name can contain any characters so it's hard to do it with regex.

这些ID中的第一个数字是另一个表的主键。我想在删除行时用触发器删除这些条目，plperl函数会很好，除非它不保留哈希的顺序，并且顺序在这个项目中很重要。我能做什么（不改变json编码配置的格式）？注意：图表名称可以包含任何字符，因此很难使用regex。

You need to use a streaming JSON decoder, such as JSON::Streaming::Reader. You could then store your JSON as an array of key/value pairs, instead of a hash.

您需要使用流式JSON解码器，例如JSON:：streaming:：Reader。然后，您可以将JSON存储为键/值对的数组，而不是散列。

The actual implementation of how you might use do this is highly dependent on the structure of your data, but given the simple example provided... here's a simple implementation.

如何使用的实际实现在很大程度上取决于数据的结构，但给定所提供的简单示例。。。这里有一个简单的实现。

use strict;
use warnings;
use JSON::Streaming::Reader;
use JSON 'to_json';

my $s = '{"Name":[[1,1],[1,2],[2,1]],"Name2":[[3,2]]}';

my $jsonr = JSON::Streaming::Reader->for_string($s);

my @data;
while (my $token = $jsonr->get_token) {
    my ($key, $value) = @$token;
    if ($key eq 'start_property') {
        push @data, { $value => $jsonr->slurp };
    }   
}   

print to_json(\@data);

The output for this script is always: -

此脚本的输出始终为：-

[{"Name":[[1,1],[1,2],[2,1]]},{"Name2":[[3,2]]}]

Well, I managed to solve my problem, but it's not a general solution so it will probably not help the casual reader. Anyway I got the order of keys using the help of the database, I called my function like this:

好吧，我设法解决了我的问题，但这不是一个通用的解决方案，所以它可能对普通读者没有帮助。无论如何，我使用数据库的帮助获得了密钥的顺序，我这样调用我的函数：

SELECT remove_from_chart(
    chart_config,
    array(select * from json_object_keys(chart_config::json)),
    id);

then I walked through the keys in the order of the second parameter and put the results in a new tied (IxHash) hash and json encoded it.

然后，我按照第二个参数的顺序遍历键，并将结果放入一个新的绑定（IxHash）哈希中，并对其进行json编码。

It's pretty sad that there is no perl json decoder that could preserve the key order when everything else I work with, at least on this project, does it (php, postgres, firefox, chrome).

令人遗憾的是，当我使用的其他所有东西（至少在这个项目中）都这样做时，没有perl-json解码器可以保留密钥顺序（php、postgres、firefox、chrome）。

@soger, thanks for the idea in your comment above from 5 years ago!

@索格，谢谢你5年前在上面的评论中的想法！

I looked into JSON::PP code and I'd just need to add a tie to IxHash at the beginning of the function called object().

Brilliant solution! Thanks for the idea. I figured out how to implement this using the Monkey::Patch module to wrap the JSON::PP::object() function to make it use Tie::IxHash, without touching the installed JSON::PP files:

绝妙的解决方案！谢谢你的想法。我想好了如何使用Monkey:：Patch模块来包装JSON:：PP:：object（）函数，使其使用Tie:：IxHash来实现这一点，而无需接触安装的JSON：：PP文件：

use Monkey::Patch qw[patch_package];

# Monkey-patch JSON::PP::object() subroutine to use Tie::IxHash.
my $handle = patch_package 'JSON::PP' => 'object' => sub {
  my $orig = shift;
  my %obj;
  tie %obj, 'Tie::IxHash' or die "tie(\%obj, 'Tie::IxHash') failed!\n";
  $orig->(\%obj)
};

After running the code above, as long as $handle remains in scope, JSON::PP::decode_json will use Tie::IxHash for all JSON objects. I tested by reading in a JSON file, decoding it with JSON::PP::decode_json, then encoded the resulting data structure back into JSON with JSON::PP::encode_json and wrote that to a new JSON file. I then ran the original JSON file and the new JSON file through jq . to normalize the formatting and compared the results. They were 100% byte-for-byte identical. 👍

运行以上代码后，只要$handle仍在作用域中，JSON:：PP:：decode_JSON将对所有JSON对象使用Tie:：IxHash。我通过读取一个JSON文件进行测试，用JSON:：PP:：decode_JSON对其进行解码，然后用JSON：PP：：encode_JSON将生成的数据结构编码回JSON，并将其写入一个新的JSON文件。然后，我通过jq运行原始JSON文件和新的JSON文件。以规范化格式并比较结果。它们完全相同。👍

(Of course, ideally JSON::PP should offer this as a built-in option out of the box!)

（当然，理想情况下JSON:：PP应该将其作为开箱即用的内置选项提供！）

JSON objects are unordered. You will have to encode the desired order into your data somehow

JSON对象是无序的。您必须以某种方式将所需的顺序编码到数据中

{"Name":[[1,1],[1,2],[2,1]],"Name2":[[3,2]], "__order__":["Name","Name2"]}

[{"Name":[[1,1],[1,2],[2,1]]},{"Name2":[[3,2]]}]

May be you want streaming decoder of JSON data like SAX parser. If so then see JSON::Streaming::Reader, or JSON::SL.

您可能想要类似SAX解析器的JSON数据流解码器。如果是这样，请参阅JSON:：Streaming:：Reader或JSON：：SL。