How does the datastore system work?

[dwh]

There are some aspects of vb that are not obvious. The datastore looks interesting. Can someone familiar with the code provide an overview of how it works?

[Andreas]

Well ... datastore is nothing mysterious.

The table holds serialized content of variables (mostly arrays).

If you want to read one of those you must include the key in $specialtemplates, init.php will then load the according rows from the table into $datastore
To get your stuff use $myarray = unserialize($datastore['mykey']);
To write your stuff call build_datastore('mykey', serialize($myarray)), this function is defined in functions_databuild.php.

That's it.

[Natch]

Nice succinct answer, KirbyDE :D well done mate...

[Andreas]

Thanks. I wanted to keep bandwidth usage low ^.^

[Reeve of shinra]

If it still calls from the DB, what are the real advantages of it and what would be a good example of where to use / not use it? =p

[Andreas]

Well the advantage is that you don't need an additional query, as init.php will load all required rows with just 1 query.
So it is easy to store custom data without having to modify existing queries or introduce new ones.
I'd suse this for data that needs to be read often/all the time, but is only being updated seldom (as you can see, datastore holds things like user record, smilies, bbcode, etc).

[dwh]

Thanks. What confused me is that I started by looking at the raw data. While it doesn't quite look encrypted, it has a:n or s:n but other times it just has numbers. I don't quite get what those a: or s: stand for?

[Natch]

a = array
s = string
and the numbers indicate how many characters are included to reconstruct the object ...

[dwh]

To get your stuff use $myarray = unserialize($datastore['mykey']);
To write your stuff call build_datastore('mykey', serialize($myarray))How would you store just a string instead of a whole array?
Then how would you call it back?

I tried


$testvar="ted";
build_datastore('mytest', $testvar);

Which successfully put "ted" into "mytest" in the datastore table. However to get it back I tried
$anothertestvar=$datastore[mytest];
as well as
$anothertestvar=$datastore[testvar];

and it didn't work.

[dwh]

After putting 'mytest' in specialtemplates before calling global.php,
$datastore['mytest'] worked.