Wrong data type of fields when adding a Spatialite layer

[qgib]

Author Name: Etienne MORO (Etienne MORO)
Original Redmine Issue: 16945
Affected QGIS version: 2.18.11
Redmine category:data_provider/spatialite
Assignee: Julien Cabieces

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Using the layer BATIMENT of my spatialite DB (file attached):

1. If you look at the field properties, you can see that the field "coordX" has the type QString-TEXT, whereas in the spatialite DB, the type is FLOAT, so it should be considered by QGis as a DOUBLE (or REAL or NUMERIC) but not as a TEXT. This bug causes lots of problems if I try to create expressions using that field.
2. If I try to add a new field choosing the type 'double', QGis save it with the type FLOAT, and I think this the origin of my first problem, because until then, QGis doesn't well recognize that type FLOAT.
   This bug appears in v2.14, and v2.18.

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• Bati.zip (Etienne MORO)

[qgib]

Author Name: Giovanni Manghi (@gioman)

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It happens also on Linux, and curiously enough it does NOT happen if adding the layer by d&d from outside the QGIS main Window into QGIS.

Any other way (standard "add SL layer", DB Manager, Browser) lead to the issue.

As it really does not corrupts the data I cannot tag this as "high priority" unless is a regression from a previous QGIS version (and it may be the case, but can't try right now).

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• subject was changed from Problem managing types of fields using a spatialite layer to Wrong data type of fields when adding a Spatialite layer
• crashes_corrupts_data was changed from 1 to 0
• operating_system was changed from Windows 7 to
• priority_id was changed from High to Normal
• category_id was changed from Attribute table to Data Provider/SpatiaLite

[qgib]

Author Name: Etienne MORO (Etienne MORO)

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After several tests, I think the real problem is that in a Spatialite DB, you've got a table named geometry_columns_field_infos which isn't correctly filled when you add a field in QGis.
When you create a new field of type REAL, in the table geometry_columns_field_infos, you should fill the field double_values with the total number of rows, instead of filling the field null_values, even if all the values are NULL (at the beginning). Because after, even if you fill all the rows of the new field with real values in QGis, the table named geometry_columns_field_infos is not changed (only the field null_values is filled).

I hope this explanation will help you to correct that problem. I understand it's not a blocking problem, but it's very annoying when you try to create new data in a spatialite DB with QGis.

[qgib]

Author Name: Julien Cabieces (Julien Cabieces)

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Fixed in 3.4.2

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• assigned_to_id was configured as Julien Cabieces
• status_id was changed from Open to Closed

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• resolution was changed from to fixed/implemented