Serialize vs Implode

Question

What do you think is the better way to go about storing a few image id's inside a record in a MySQL database? It's just the image id's which will be used to fetch the images from a different library.

Do i implode the id's in the record like 1#4#7#9#10#12 or do I just serialize the array and store that? Are there any performance benefits by using the one instead of the other? Stability preferences?

I have just always used implode and explode, never really gave it much thought. Thanks.

Answer 1

I would pefer serialize or JSON-encode.
It is more flexible and for example will allow you to add image title and other details there in future...

Answer 2

As far as I know there are not significant differences in this case but implode() is a bit faster since it assumes an array and serialize() does not know what you are passing to it.

EDIT based on OP's comment:

Well all the images are stored in a seperate library table with the title and descriptions and things like that. But yeah I see your point.

In that case is not a good idea so serialize several IDs into a single field. What you need is a *-to-Many relation between your 2 tables. This is the correct way of represent multivalued fields:

+----------------------+
|  USER                |
+---------+------+-----+
| user_id | name | ... |
+---------+------+-----+

+----------------------+
|  USER_PICTURE        |
+---------+------------+
| user_id | picture_id |
+---------+------------+

+--------------------------+
|  PICTURE                 |
+------------+-------+-----+
| picture_id | title | ... |
+------------+-------+-----+

Answer 3

If you don't want to (over?)normalize your tables, and you really just want to store a list of ids then I suggest using a simple comma-separated list, because already MySQL has some functions which can directly deal with comma-separated string values:

FIND_IN_SET: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_find-in-set

SELECT FIND_IN_SET('b','a,b,c,d'); --> 2

CONCAT_WS: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_concat-ws

SELECT CONCAT_WS(',','First name',NULL,'Last Name'); --> 'First name,Last Name'

Of course, you won't be able to do SQL JOINs, but it still can be helpful.

Answer 4

My friend, serialization is to obtain a string representation of an object's status. Even if it works i don't think is the best way to do what you want. I would prefer to store a json object with the ids. Because a json object is multiplatform, is a string and is easily readable by a human i think is a good approach.