Extension talk:Cargo

Referata
I've read about this new extension on mediawiki-l. Thanks for working on it, I'm impressed. I've read the FAQ item about performance and I wonder if you already have enough data to prefer Cargo on some of your wikis out of performance concerns, or whether you'd need some testing.

In particular, as our generous host for http://wikipapers.referata.com/, you just have to ask and I'll do anything possible to migrate. Especially if it reduces hosting costs/effort for you. --Nemo 01:09, 17 January 2015 (UTC)


 * I'm glad you think it's interesting! I have no performance data on Cargo yet. I didn't understand the second part - are you asking about having Cargo on Referata, or something else? Yaron Koren (talk) 23:45, 18 January 2015 (UTC)


 * Yes, I'm asking about Cargo on Referata. If switching to this extension makes your job of running Referata wikis easier, I'd feel obliged to help. --Nemo 23:51, 18 January 2015 (UTC)


 * Oh, I see. I do plan to install Cargo on Referata, though it wouldn't require any switching - just adding the additional extension. I will probably do that in the next few weeks. Thanks for your offer to help. Yaron Koren (talk) 00:55, 19 January 2015 (UTC)

Compatibility with SMW
Hi Yaron

Will future versions of SF support SMW as well as Cargo or will new versions of SF only support Cargo?

Many thanks

Duncan (17 Jan 2015)


 * I have no plans to drop support for SMW in SF. Yaron Koren (talk) 23:46, 18 January 2015 (UTC)

Not working
I am basically c/p the code from the example pages and change the references to the properties, but I fail to get it going. I always get the following two errors:
 * storing it:
 * This template defines the table "Name". This table has not been created yet.


 * querying it:
 * Error: no database table exists for "Name".

I do not get it. --Temptuousinsolence (talk) 11:15, 20 January 2015 (UTC)


 * You're just missing one step: in the template page, you need to select the "Recreate data" tab, then press the button. That should be explained better in the documentation. Yaron Koren (talk) 13:55, 20 January 2015 (UTC)

Error on Special:ViewData
I have a fresh MW+Cargo installation on localhost. I proceded thru the Quick-Start-Tutorial. Everything seems fine. Tables were created. Forms are working, Drilldown is running, too.

But on Special:ViewData I only get the error: "A database query error has occurred. This may indicate a bug in the software."

I have: MediaWiki 1.24.1 PHP 	5.6.3 (apache2handler) MySQL 	5.6.21 Cargo	0.5.1

Any suggestions? Thanks for help!


 * I'm glad that you got everything working! Special:ViewData is, for now, only a "helper" special page - it's used by the interface, but users aren't supposed to go there directly. I should change that page, though, to display a more helpful message if users do go there. Yaron Koren (talk) 14:50, 21 January 2015 (UTC)

Error after creating Cargo-Tables and View Table
After creating a template and creating corresponding Cargo-Tables (everthing fine till this step) I clicked the "view Tabele"-Link and got this Error: A PHP-Warning Notice: nserialize: Error at offset 594 of 600 bytes in _MYPATH_/CargoTableSchema.php on line 17 and one the page itself this Error: Internal error [e39d5d76] 2015-01-21 13:29:18: Fatal exception of type MWException


 * That sounds bad. (I assume the notice message was for "unserialize", not "nserialize".) I'm guessing that this is a character-encoding issue in some way. If possible, could you add this line right above line 17 of CargoTableSchema.php:

print $dbString;


 * ...and let me know what it prints out? Yaron Koren (talk) 15:09, 21 January 2015 (UTC)


 * Thanks for the fast answer. Although I have a German-Wiki and tables I tried to avoid wired letters. My wiki is about US-Military-Trials after WW II... Here is the printout:

a:11:{s:10:"Angeklagte";a:3: {s:4:"type";s:4:"Page";s:6:"isList";b:1;s:9:"delimiter";s:1:",";}s:6:"Zeugen";a:2:{s:4:"type";s:4:"Page";s:6:"isList";b:1;}s:7:"Richter";a:3: {s:4:"type";s:4:"Page";s:6:"isList";b:1;s:9:"delimiter";s:1:",";}s:11:"Verteidiger";a:3: {s:4:"type";s:4:"Page";s:6:"isList";b:1;s:9:"delimiter";s:1:",";}s:18:"Staatsanwaltschaft";a:3: {s:4:"type";s:4:"Page";s:6:"isList";b:1;s:9:"delimiter";s:1:",";}s:6:"Beginn";a:1:{s:4:"type";s:4:"Date";}s:4:"Ende";a:1: {s:4:"type";s:4:"Date";}s:16:"AnzahlTodsstrafe";a:1:{s:4:"type";s:7:"Integer";}s:16:"AnzahlAngeklagte";a:1: {s:4:"type";s:7:"Int
 * Maybe my Template is wrong and caused the error?


 * Great, that was very helpful. It turns out that the issue wasn't character encoding, but just that I didn't make the "table_schema" field in the "cargo_tables" database table big enough; sorry about that. I just fixed this problem in the Cargo.sql file. If you know how to modify MySQL tables (directly or via phpMyAdmin or such), if you just make that change, then re-save that template and recreate its data, the problem should go away. Yaron Koren (talk) 17:13, 21 January 2015 (UTC)


 * Great, that I can help by occuring errors ;-) I fixed it - no problems anymore. What size will you set for table_schema in the next version?


 * Oh, oops, I didn't actually specify what change to make! I'm glad you got it working anyway. The change I made was to change the type from VARCHAR(600) to BLOB, which should allow for an essentially unlimited size for the schema. Yaron Koren (talk) 21:30, 21 January 2015 (UTC)

Selecting calculated columns
I see that it's possible to select fields like COUNT(*). Is it possible to do more complex selections like the following?

I'm guessing not, since the commas in the if-statement would probably be interpreted as field separators. Any chance a custom separator could be defined similar to some SMW syntax? So a cargo query could be like:

--Jamesmontalvo3 (talk) 19:56, 27 January 2015 (UTC)


 * Actually, Cargo does a "smart split" on the "fields" parameter, ignoring commas contained within parentheses, so in theory just using commas should work there, though I haven't tried that particular query. Yaron Koren (talk) 01:04, 28 January 2015 (UTC)