PHP：关键字搜索：查找字符串中的子字符串

Question

I am building a comics website and have implemented a search. The search originally used the image title... This worked fine:

if (strtolower($input)==strtolower(substr($row['title'],0,strlen($input)))) {

But now I feel that many people won't remember the title. So I've added a column to the database called "keywords", varchar [55]... and my test entry is the string "five, second, rule, food, rules". I figured I could replace $row['title'] with $row['keywords'] and the search would still work.

It worked if I start searching from the beginning of the string, like I enter "five, seco..." But not if I start from the middle of the string, like "second", or "rule", etc.

Any ideas on how I can make that work?

Thanks!

Answer 1

Doing it in a comic's column will only bring tears as it breaks normalization. What you should do is make a keyword table that has one word per entry and then a pivot table that matches keywords to comics. Then you can just do a join to find all the comics that match.

It's more work to setup, but more flexible in the long run.

EDIT:

Keyword table:

id     keyword
1      x-men
2      action
3      mystery
4      batman
etc.

comic_keyword table

comic_id    keyword_id
45          3
678         1
678         2
77          3
77          4
etc.

The second table (the pivot table) matches the ids of the comic to the ids of the keywords they're associated with. That's how many-to-many relationships should be modeled in most cases.

Answer 2

The straightforward solution would be to use stripos instead:

if(stripos($input, $row['title']) !== false) {
    // row matches
}

However, this isn't really a good solution. It would be much better to offload the filtering to your database, so non-matching rows don't have to make the trip to your front end at all. If you keep keywords as a comma-separated field then LIKE or REGEXP would be a good choice of tool; if you normalized your database schema so that the 1-to-many relationship of comics to keywords is modeled with a separate comic_keywords table then matching would be even easier.

For example, assuming that comic has an id and comic_keywords has a comic_id and a keyword , you could select matching comics with

SELECT DISTINCT(comic_id) FROM comic_keywords WHERE keyword = 'blah'

Answer 3

You can split the column on the fly:

if (in_array(strtolower($input), explode(', ', $row['title']))) {
  /* found it */
}

Answer 4

看起来你需要Sphinx或（不太可能，但更容易设置） MySQL的全文搜索 。