Ingre Ogr Enhancement

[zhenchen17]

This patch enhances Ingres Ogr drivers as follows:

1. Add two key words to the connection string that are used in database authorization. effuser is for the real user in database dbpwd is for the password of the effuser

It fits the situation that OS authorization user is not the same name with database user name. Ingres requires double authorization check.

2. Enhance EPSG srid search in database. The previous method is to match the text string representation of a EPSG srid. It is not accuate if there is minor different. Now before a text matching search, a query is execute directly to get the srs_id and confirm: SELECT srid FROM spatial_ref_sys WHERE auth_name = 'EPSG' and auth_srid= %s

3. Using system maintained sequence for each fid field in each table instead of the global defined sequence:

notice: this feature is supported since Ingres 9.3

[zhenchen17]

patch file