Need information about atrributes

I’m mentaly working on a tutorial on build scripts, but I still can’t seem to get my head around exactly what these do and how to decide what they should be set to:

XPDO_TRANSPORT_UNIQUE_KEY
XPDO_TRANSPORT_UPDATE_OBJECT
XPDO_TRANSPORT_PRESERVE_KEYS

And, are there other attributes that should be covered in the tutorial?

Quote from: BobRay at Dec 01, 2008, 06:35 PM

XPDO_TRANSPORT_UNIQUE_KEY

Optional attribute which defines a column or array of columns which identify a data object uniquely. If not specified, the primary key (i.e. native key) is used for lookups of existing objects in the target deployment.

Quote from: BobRay at Dec 01, 2008, 06:35 PM

XPDO_TRANSPORT_UPDATE_OBJECT

Optional attribute which defines if existing objects should be updated or left alone if found in the target deployment. The default is false.

Quote from: BobRay at Dec 01, 2008, 06:35 PM

XPDO_TRANSPORT_PRESERVE_KEYS

Optional attribute indicating if an object’s primary key should be preserved. If false, the key is discarded and a new one generated. Objects that do not preserve their keys must be able to generate their own keys (i.e. auto increment primary key value in MySQL). The default is true.

Quote from: BobRay at Dec 01, 2008, 06:35 PM

And, are there other attributes that should be covered in the tutorial?

Likely; I’ll see if I can’t create a wiki page with additional information.

Thanks, that answers the first question. I’m still not sure, though, under what circumstances I would want to change the default values (except for UPGRADE, which is obvious even for me).

Can you give some examples of cases where you’d want to change the defaults?

Still wonding about this -- especially XPDO_TRANSPORT_PRESERVE_KEYS. I notice that XPDO_TRANSPORT_PRESERVE_KEYS is set to false in the Captcha package and UNIQUE_KEY is set to ’key’. I’m not sure if I did that or if splittingred did when he edited it.

Will that cause any problems?  Should they be changed?


Looking in SVN, I see that many components use the defaults, so XPDO_TRANSPORT_PRESERVE_KEYS is set to true, but a number of them have PRESERVE_KEYS set to false (e.g. ditto, weblogin). I have no idea why.

Quote from: BobRay at Dec 11, 2008, 11:30 PM

Still wonding about this -- especially XPDO_TRANSPORT_PRESERVE_KEYS. I notice that XPDO_TRANSPORT_PRESERVE_KEYS is set to false in the Captcha package and UNIQUE_KEY is set to ’key’. I’m not sure if I did that or if splittingred did when he edited it.

I did that, for the System Settings you are adding in - because the unique identifier for the system settings table isn’t ’name’, it’s ’key’ (there is no name field).

Also, PRESERVE_KEYS is false in the actual plugin, because you don’t want to preserve the PK there...the PK is ’id’, and is an auto-increment SQL field. PRESERVE_KEYS should always be false when dealing with objects that use auto-increment fields. It’s true on the System Settings because we want those PKs (key) to stay the same as in the build.

Looking in SVN, I see that many components use the defaults, so XPDO_TRANSPORT_PRESERVE_KEYS is set to true, but a number of them have PRESERVE_KEYS set to false (e.g. ditto, weblogin). I have no idea why.

Most all the snippets use PRESERVE_KEYS set to false on their snippet or plugin objects; if they don’t, they’re wrong.

Ok, so if I look at the object I’m creating or updating in the DB and see the PK with an auto_increment setting, PRESERVE_KEYS should be set to false?

It looks like the Captcha build file doesn’t set PRESERVE_KEYS for the plugin, but looking at the xpdovehicle class code, it appears that the default is false. If Jason mistyped the default value in his message above, then those snippets I was talking about are ok and I’m less confused.