[fdo-internals] xmin and xmax are reserved keywords

Mateusz Loskot mateusz at loskot.net
Mon Jan 15 10:40:21 EST 2007

Brent Robinson wrote:
> Hi Mateusz,
> Does PostGIS support double quote delimiting for table and column names
> in select statements?
> If it does then another option might be to double-quote delimit these
> names in the select statements issued by the Schema Manager. This would
> be a fairly small change to utilities/SchemaMgr/src/Ph/Field.cpp.


As Paul already explained, it's not feasible.

What about a simple indirection - querying provider's Schema
manager for column name. For example:

1. ctor of FdoSmPhSpatialContextGroupReader already accepts physical
manager of given provider.

2. In the class FdoSmPhSpatialContextGroupReader, the pointer to this
manager could be saved.

3. Next, whenever functions like
FdoSmPhSpatialContextGroupReader::GetXMin() are called, first, the
reader asks physical manager for column name using ie. enumerator to
identify which column name is requested.
Here, I assume the set of column names in f_* meta schema is well-known
 and constant.

4. In the FdoSmPhMgr, we can add new API similar to GetDcColumnName() or
extend existing GetDcColumnName(), which can be called from GetXMin()
and return default *or* provider's specific column name.

5. If no implementation is provided by a FDO provider, then default
column name is returned by manager itself.

6. If a provider (re)implements the column name API in FdoSmPhMgr,
class, then provider's specific name is used in in the
FdoSmPhSpatialContextGroupReader class.

Would it work for you?

Mateusz Loskot

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