[Qgis-developer] New feature: RFC saving style and ui in Spatialite

Gino Pirelli luipir at gmail.com
Mon Mar 3 02:28:50 PST 2014


regarding this feature I produced PullRequest:

https://github.com/qgis/QGIS/pull/1221

thank you

Luigi Pirelli (luigi.pirelli at faunalia.it - luipir at gmail.com)

On 28 February 2014 15:58, Gino Pirelli <luipir at gmail.com> wrote:

> regarding how to implement saving SLD in spatialite i downgraded my
> previous using simple text field... avoiding blob or XmlBlob (SL>4.1)
>
> the reason is to allow more simpler interoparability reading back sld.
> Using directly text I can read it's value directly. values are utf8
> enconded and reading them outside qgis context (I received some comments
> about this) it's simple to understand that text value has a locale coding.
>
> - I decided to avoid sqlite blob because of to simplify interoperability
> avoiding blob decoding step that it's less uman "natural"
> - I decided to avoid XmlBlob format because it's available only with SL >
> 4.1. I plan to use this data type when SL 4.1 will be more used. At the
> moment I preferred to allow this functionality available in all platform
> and distribution in witch  qgis is available and in some of them (e.g.
> debian wheezy, Ubuntu 13) SL 4.1 it's not packaged.
> - I hope to add the same functions to the the new GeoPackage, but this
> it's not still planned.
>
> please let me know if there are comments
>
> code is here:
> https://github.com/luipir/QGIS/tree/spatialite-savestyle
>
> diff is here:
> https://github.com/luipir/QGIS/compare/spatialite-savestyle
>
> thank you,
>
> Luigi Pirelli (luigi.pirelli at faunalia.it - luipir at gmail.com)
>
>
> On 5 February 2014 13:18, Gino Pirelli <luipir at gmail.com> wrote:
>
>> Hi,
>>
>> I'm developing a new feature to save SLD and ui in Spatialite provider in
>> the same way this function is available for postgres.
>>
>> this function developed for Faunalia is funded by ARPA Piemonte
>> fork is available at:
>> https://github.com/luipir/QGIS/tree/spatialite-savestyle
>> and actual modification are localized in this
>> commit: f058bea1fe51116b8231eb5c1ca4faee485c38b2
>>
>> there are some question about how to develop it and are related how to
>> manage XML in a sqlite/spatialite table.
>>
>> this code derive by the postgres provider code where QML and UI xmls are
>> recorded in a XML column. XML is a postgres type. This type is not
>> available in SQlite but it's available in SL 4.1> (called XmlBlob [1])
>> In this preliminary commit XML is saved in a text column, but saving XML
>> as a blog (blob type in sqlite or XmlBlob in SL) have the advantage to
>> avoid all encoding problems.
>>
>> so the question is... sqlite blob or spatialite xmlbob?
>>
>> Blob type can't allow XML parsing using SQL queries
>> XmlBlob allows this (using libxml2)
>>
>> Blob type is sqlite native type
>> XmlBlob can be used only with SL 4.1>
>>
>> My preference is to use native data type Blob. What's you opinion about
>> blob/ xmlblob or whatever
>>
>> regards,
>>
>> Luigi Pirelli (luigi.pirelli at faunalia.it - luipir at gmail.com)
>>
>> [1] https://www.gaia-gis.it/fossil/libspatialite/wiki?name=XmlBlob-intro
>>
>>
>
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