Arrays and MySql

[nogeekyet]

I am building a two dimensional array and write it as part of a record to a table. In MySql I have defined the field for the array as "varchar, length 300". I seem to be able to write it without errors but I cannot get it back. Using a print_r or var_dump on

$TimeLog 

I cannot see any of my data. code=php$TimeLog = $row['U_TimeLog'];[/code]. Any ideas on handling arryas in mysql?:o

[Bjom]

yes. for saving arrays in a way that you can retrieve them in array form you need the serialize and unserialize funtions.

[halojoy]

Bjom;10942837 wrote:

yes. for saving arrays in a way that you can retrieve them in array form you need the serialize and unserialize funtions.

Basically what [man]serialize[/man] does:
turn an Array into one String

And [man]unserialize[/man] does:
turn a String back into original Array

And to store STRINGS, VARCHARS, TEXT in database is perfectly good!

[Ac1ds0ld13r]

I'm actually getting ready to cross this bridge myself with a project and some of the looking around I've done recommended using implode and explode.

Found Herel. Is one preferred over another?

[bradgrafelman]

After reading the article, and seeing this:

One of the trickier concepts to tackle is the idea of arrays. In short, arrays allow you store multiple sets of data to one variable

I have to wonder if the person who wrote that article has even heard of database normalization.

In fact, upon further reading, I can confirm that he/she has not:

You may not need 5 fields now, but in the future you may want to assign 5 categories to one book. Then what do you do?

What you do is create one table that holds all possible categories, one table that holds metadata for a given book, and then one table that associates that book with however many categories are applicable. You don't try to cram multiple values into one column.

EDIT: Also, to answer your question, m opinion is that implode/explode is the worst way to go about doing something like this (not that you should do this at all anyway). If you're trying to store an array as a string, then serialize/unserialize is the way to go. Using implode/explode runs the chance of picking a delimiter that may appear in the data.

[Ac1ds0ld13r]

bradgrafelman thank you for your answer! That pretty safely wrapped this up for me. My project is looking at 1000+ entries fairly quickly, and while there's only going to be a few arrays, seems like the more calls I get the more chances there are for things to awry.

If i read the tone of your posts correctly it seems you don't recommend storing an array either? Assuming I didn't forget how to read and that is the case: What would you say is the best method for storing array data then?

And if someone feels Im hijacking the thread let me know and I'll make another :queasy: Just seemed my question was relevant to the first.

[bradgrafelman]

Ac1ds0ld13r;10944090 wrote:

If i read the tone of your posts correctly it seems you don't recommend storing an array either?

That's correct. Storing an array implies that you're storing multiple items in one column, something which pretty well violates the first normal form.

Ac1ds0ld13r;10944090 wrote:

Assuming I didn't forget how to read and that is the case: What would you say is the best method for storing array data then?

Separating it out and using a normalized DB schema. I gave an example above in regards to assigning multiple categories to a single book - the same basic principle applies when normalizing any type of data.

I'd highly recommend finding a good article/tutorial that deals with database normalization.

[djjjozsi]

here is an answer generator to create relations between two tables.
Answer generator

In the form you can see: commadelimitered_field

This means you will get a better idea then you store the listed IDs in a comma delimitered field.

Feel free to ask 🙂

[bradgrafelman]

djjjozsi;10944101 wrote:

then you store the listed IDs in a comma delimitered field.

...which violates the first normal form.

[djjjozsi]

read carefully, please:

This means you will get a better idea then you store the listed IDs in a comma delimitered field.