[Resolved] Convert: numbers -> string -> numbers

halojoy

.
In my database (not mySQL!) I want to store an array of integer ID numbers:
$idnumbers = array ( 23, 2, 35, 15, 4 );
into one string field (column).

I was thinking of putting these numbers into a $string.
Save this as a text $string in my database.
Get the data back and make an integer array again.

I guess I should need an 'delimiter' (divider character), maybe even a space can be used,
to separate these numbers inside the string.

1. How to read $idnumbers() into text $string ?
2. How to convert $string back to an integer array $idnumbers()

thanks

jorday

1. How to read $idnumbers() into text $string ?

<?
$string = implode(",",$idnumbers);
?>

As said below, and my other method didn't work! :/

2. How to convert $string back to an integer array $idnumbers()

<?
$idnumbers = explode(",",$string);
?>

laserlight

I want to store an array of integer ID numbers

Why do you want to store an array of integer ID numbers?
i.e. what relation do these numbers have in the schema of your database?

The solution is simple: for storing into the database [man]implode/man the array into a string (using say commas to separate the integers), then [man]explode/man the string into an array after retrieval from the database.

But if there's a better way to integrate what you're trying to do with your database structure itself, then you should go by that route instead.

halojoy

Question:

Why store an array of of ID-numbers?

Those numbers are a list of pointers to ID-num of records in another table.
It is a group of records that belongs together in that other table.

Thanks for both solutions.
I was also think of implode and explode as being suitable functions.

leatherback

Sounds to me like you ar esetting yourself up for a lot of headaches and frustation in the future.

You hsould use a between-table in which you store the table1.id and the table2.id. This way you can create many - to many relations between tables.

It sounds to me tha that is what you are trying to do.

laserlight

Those numbers are a list of pointers to ID-num of records in another table.
It is a group of records that belongs together in that other table.

Ah. In that case, you might want to look into using a third table instead, as it appears that you have a many-many relationship between the tables concerned.

Read Database Normalization And Design Techniques (all the way to 4th normal form) for a more detailed explanation.

halojoy

Originally posted by leatherback
You hsould use a between-table in which you store the table1.id and the table2.id. This way you can create many - to many relations between tables.

Even if these nice advices are out of topic of this thread, I will give a short answer:
I wont create a new table, only for this.
Why should I, when I can do as I mentioned.

Anyway, whether it will give a headache or not, I go for my original plans.
Because I am the only one, that can see whole picture of my project.

Thanks for solution, everybody.
Now I go write my coding, using implode and explode.

🙂

laserlight

I wont create a new table, only for this.
Why should I, when I can do as I mentioned.

Well, in the end it is your judgement call. It may be that you will never have to process many, many such indices, and so will not face a performance problem. But wisdom gathered from both theory and implementation in large scale projects tells us that normalising one's database is usually better than using such a hack.

halojoy

.
.. large scale projects ...

I am not into any large scale projects.
Rather into mini mini mini
😃 😃