QGIS » QGIS Application

After more testing: Saving and loading styles in Spatialite db depends on provider type, QGIS version and probably GDAL version. As a result, saving default style is unreliable.

Test results¶

- 2.18.13@Debian Jessie (GDAL 1.x):¶

- Loading the default style from the source database   

• SpatiaLite provider requires the proper file path in layer_styles.f_table_catalog in order to find the style.
  It also means the style is not fully portable, as the file path must match.

• OGR provider doesn't require it, the value may be NULL or wrong (although if there are more than one record with the same
  useAsDefault value, the one with proper path is preffered).

- Saving default style to the datasource database

• For OGR provider based layers: sets layer_styles.f_table_catalog to NULL, so the style will be only readable for the OGR provider.

• For SpatiaLite provider based layers: sets proper value to layer_styles.f_table_catalog, so the style will be accessible for both
  providers.

- Saving default style to the local database

• For OGR provider based layers: saves to a .qml side file, so the style will be readable for the OGR provider only.

• For SpatiaLite provider based layers: saves to the qgis.qmldb database, so the style will be readable for both providers

- 2.18.13@Windows (GDAL 2.x):¶

- Works similarly, but if the geometry column is uppercase ("GEOMETRY" in my case), there are two new requirements related to the
      geometry column name comparision:

• OGR provider: layer_styles.f_geometry_column value must be uppercase as well

• SpatiaLite provider: layer_styles.f_geometry_column value MUST BE LOWERCASE (sic!)

- 2.99@Debian Buster (GDAL 2.x):¶

- OGR provider: As previously, saves with null path and reads correctly styles saved by itself

- Spatialite provider: BROKEN. REGRESSION. Sets two colmuns: layer_styles.f_table_catalog and f_table_schema to NULL. 
      Neither provider can load the style. A manual updating the f_table_schema value to '' makes it readable for OGR. 
      Despite tweaking the f_table_catalog value, I didn't manage to make it readable for the Spatialite provider (itself).

- I couldn't test the uppercase geometry column problem because of the regression above.

- 2.14:¶

- Let's forget about 2.14 as some conditions must be literally opposite to make it working in 2.14 
      (e.g. f_table_catalog must be empty for the Spatialite provider).

Identified bugs prority:¶

1. Default style saving for SpatiaLite provider is broken in QGIS 3 (regression)

2. SpatiaLite provider should fallback to record with empty/wrong f_table_catalog value, as OGR does. 
       Actually I don't see any use of this redundant value, as everything applies for the same file. (could be fixed for QGIS 3.0 and 2.18)

3. Handling uppercase-named geometry column is broken, probably in QGIS 2.18 with GDAL 2.x