PHP/RegEx-表名前面的逻辑 [英] PHP/RegEx - Logic for prepending table names

问题描述

因此，我正在尝试构建一个脚本，该脚本以适当的表前缀自动为有效的列名加上前缀(例如"t."或"r.")

So I'm trying to build a script that automagically prepends valid column names with its appropriate table prefix (e.g. "t." or "r.")

$t_columns = array('id', 'name', 'label');
$r_columns = array('related_value');

输入:

id > 1 AND (name = 'Hello' OR label IN ('World', 'Planet name AND label')) AND (related_value > 1 AND related_value < 50)

输出:

t.id > 1 AND (t.name = 'Hello' OR t.label IN ('World', 'Planet name AND label')) AND (r.related_value > 1 AND r.related_value < 50)

请注意，您不能执行常规的 str_replace .什么是最简单的代码(我猜是 preg_replace )，以确保所有表名都正确地加上了前缀?

Notice how you can't do a normal str_replace. What would be the simplest code (I'm guessing preg_replace) to ensure that all table names are properly prepended?

推荐答案

这可以通过多种方式完成，也可以使用正则表达式.我个人将使用数组方法.首先，我将以这种方式定义修改表:

This can be done in a lot of ways, and also using regex. I'd personally use an array approach. First of all, I'd define the mangling table this way:

$table = array(
    'id' => 't.id',
    'name' => 't.name',
    'label' => 't.label',
    'related_value' => 'r.related_value'
);

这将简化str_replace()调用:

This will make a lot easier the str_replace() call:

function mangling(&$v, $k, $table)
{
    if (($k & 1) == 0)
        $v = str_replace(array_keys($table), array_values($table), $v);
}

$spans = explode("'", ' ' . $input);
array_walk($spans, 'mangling', $table);
$output = implode("'", $spans);

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