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OLEDB Data Provider Development

Posted on 2002-04-18
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Last Modified: 2013-12-03
I am developing OGC data provider component(Data Provider component which satisfies OPEN GIS Simple Feature Spec., so that can handles geometry data.) using ATL Provider template library.
I want to support ITableDefinition interface, especially CreateTable method.
The CreateTable method requires Column Properties to define columns of a table(especially geometry column).

So, I

1. define custom Column Property set  in .h file as follows (to give an ability to data provider defining geometry column to table):

DEFINE_GUID(DBPROPSET_OGIS_COLUMN, ...);

#define OGIS_PROPERTY_SET 0x1000L

enum DBPROPOGISENUM {
 DBPROP_OGIS_GEOM_TYPE = OGIS_PROPERTY_SET + 128,
 DBPROP_OGIS_EXTENT_MINX = OGIS_PROPERTY_SET + 129,
 ...
};

2. add property string to data provider's .rc file as follows :

Property      : OGIS_GEOM_TYPE
Property Constant ID  : PROP_OGIS_GEOM_TYPE
Property String Table ID  : IDS_PROP_OGIS_GEOM_TYPE
Property Description : “Geom type”
...

3. and add property set map to session object(or Data Source Object, which is right?) as follows :

...
BEGIN_PROPERTY_SET(DBPROPSET_OGIS_COLUMN)
    PROPERTY_INFO_ENTRY_EX(OGIS_GEOM_TYPE, VT_UI4, DBPROPFLAGS_COLUMN|DBPROPFLAGS_READ|   DBPROPFLAGS_WRITE, 1, 0)
...
    PROPERTY_INFO_ENTRY_EX(OGIS_EXTENT_MAXX, VT_R8, DBPROPFLAGS_COLUMN | DBPROPFLAGS_READ| DBPROPFLAGS_WRITE, 1, 0)
END_PROPERTY_SET(DBPROPSET_OGIS_COLUMN)
...


But, In VB test application, the newly defined properties(Geom type, ... etc) does not appear.... T.T

Dim conn As ADODB.Connection
 
Set conn = New ADODB.Connection
   
connStr = "Provider=..."
   
conn.Open connStr

For Each prp In conn.Properties
      Debug.Print prp.Name, prp.Value
Next prp

=====================================================================================
Sorry for my poor English ^^;

Did anyone ever have this problem before? or Any clues?

Thanks a lot in advance.
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Question by:choisk
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1 Comment
 
LVL 2

Accepted Solution

by:
SChertkov earned 300 total points
ID: 6979679
After init you provider in IDBInitialize::Initialize
ADO request properties IDBProperties::GetPropertyInfo
ONLY in categories DBPROPSET_DATASOURCEALL, DBPROPSET_DATASOURCEINFOALL, DBPROPSET_DBINITALL,
DBPROPSET_SESSIONALL.
Relationship between special GUID and you properties
GUID hardcoded in ATL. Therefore VB not show
any custom property set in connection properties
in ATL providers.

Next, i think that you must define you property
set in Rowset and Command, not in DataSource object, because column properties supported OLE DB in
command and rowsets. Also, you can try to define you properties direct in DBPROPSET_ROWSET where appropriate.


Sorry my english too.
Semyon.
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