[mapserver-dev] Layer names in OGR connection strings (undocumented feature causing problems)

[Smith, Michael ERDC-CRREL-NH]

Comma separated table names is also part of the OCI connection

"OCI:userid/password at database_instance:table,table"

http://www.gdal.org/ogr/drv_oci.html

From: Brent Fraser <bfraser at geoanalytic.com<mailto:bfraser at geoanalytic.com>>
Organization: GeoAnalytic Inc.
Date: Monday, March 4, 2013 5:25 PM
To: Tamas Szekeres <szekerest at gmail.com<mailto:szekerest at gmail.com>>
Cc: "mapserver-dev at lists.osgeo.org<mailto:mapserver-dev at lists.osgeo.org>" <mapserver-dev at lists.osgeo.org<mailto:mapserver-dev at lists.osgeo.org>>
Subject: Re: [mapserver-dev] Layer names in OGR connection strings (undocumented feature causing problems)
Resent-From: Michael Smith <michael.smith at usace.army.mil<mailto:michael.smith at usace.army.mil>>

Tamas,

  No doc that I know of.  I knew of the technique of adding comma-separated table names to connection strings from years ago when I was trying to improve the performance of an ODBC connection (http://www.gdal.org/ogr/drv_odbc.html).  Stating the table names relieves the driver from enumerating all the tables (and views etc) in the schema.  Maybe I had reviewed the source code; I can't recall...

Best Regards,
Brent Fraser

On 3/4/2013 2:20 PM, Tamas Szekeres wrote:
Brent,

Could you point me to the documentation where this syntax is mentioned? Is this specific to OGR tile indexes?

Best regards,

Tamas



2013/3/3 Brent Fraser <bfraser at geoanalytic.com<mailto:bfraser at geoanalytic.com>>
Tamas,
  if I understand correctly you are talking about connection strings like:

        CONNECTIONTYPE OGR
        TILEINEX "PG:dbname='PN2010_0911' host='thinkcentre1' port='5432' user='PN2010_0911' password='PN2010_0911',images"

note the comma and table name at the end.
See http://lists.osgeo.org/pipermail/mapserver-dev/2011-April/011194.html



Best Regards,
Brent Fraser

On 3/3/2013 2:09 PM, Tamas Szekeres wrote:
Hi,

According to a commit (made 11 years ago) in rev1370<http://trac.osgeo.org/mapserver/changeset/1370>  the OGR connections strings are being split by the comma separators, see the following fragment in msOGRFileOpen:

     papszTokens = CSLTokenizeStringComplex( conn_decrypted, ",", TRUE, FALSE );

    if( CSLCount(papszTokens) > 0 )
      pszDSName = CPLStrdup( papszTokens[0] );
    if( CSLCount(papszTokens) > 1 )
      pszLayerDef = CPLStrdup( papszTokens[1] );

This behaviour causes issues if the syntax of the connection string may normally expect commas, like with the issue: http://trac.osgeo.org/gdal/ticket/4885


Does it make sense to split the connection strings this way?

According to the OGR driver documentation<http://mapserver.org/en/input/vector/ogr.html> the layer definitions should go to the DATA section and not to the CONNECTION section.

I'd be in favour of removing this fragment from the code but I'm not sure about all consequences.


Best regards,

Tamas





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