[GRASS-dev] [GRASS GIS] #3071: v.db.join: fails with SQLite because of lower/UPPER case issues

GRASS GIS trac at osgeo.org
Thu Jun 23 14:18:00 PDT 2016

#3071: v.db.join: fails with SQLite because of lower/UPPER case issues
 Reporter:  sbl          |      Owner:  grass-dev@…
     Type:  defect       |     Status:  new
 Priority:  normal       |  Milestone:  7.0.5
Component:  Default      |    Version:  unspecified
 Keywords:               |        CPU:  Unspecified
 Platform:  Unspecified  |
 v.db.join fails when target and other table have columns with the same
 names but different cases: e.g. ID and id

 Here is an example to reproduce:
 wget -N http://www.grassbook.org/wp-

 # check original map attributes
 v.db.select geology column=GEO_NAME,SHAPE_area

 # import of CSV table
 db.in.ogr input=nc_geology.csv output=nc_geology

 # work on copy of geology map in current mapset
 g.copy vector=geology,mygeology

 # Add uppercase column, which are lowercase in other table
 v.db.addcolumn map=mygeology column="GEOL_ID text"
 v.db.addcolumn map=mygeology column="LONGNAME text"

 # Fill join column
 v.db.update map=mygeology column=GEOL_ID query_column=GEO_NAME

 # check column names of vector map attributes
 v.info -c mygeology

 # check column names of legend table
 db.describe -c nc_geology

 # join table using key columns (map: "GEOL_ID"; table: "geol_id")
 v.db.join map=mygeology column=GEOL_ID other_table=nc_geology


 Please find attached a diff which should fix the issue.

 However column case handling might need some more deliberation, since e.g.
 PostgreSQL handles uppercase column names (when quoted).
 So comparing column names case-insensitive (as in the diff) is probably
 only a hack...?

 Finally, I was wondering if it is OK that v.db.join possibly overwrites
 data in the target if both have column names in common (e.g. "cat")...
 Maybe better to add a flag to allow overwriting column content?

Ticket URL: <https://trac.osgeo.org/grass/ticket/3071>
GRASS GIS <https://grass.osgeo.org>

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