NEW ODBC DRIVER v.0243

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От Byron Nikolaidis
Тема NEW ODBC DRIVER v.0243
Дата
Msg-id 356DD412.89AD108B@insightdist.com
обсуждение исходный текст
Список pgsql-interfaces
Hello,

There is a new odbc driver v.0243 at our website
http://www.insightdist.com/psqlodbc

This version works with the odbc cursor library, thus adding positioned
updates, static and block cursors, extended fetches, etc. to the
functionality of the driver.  This is good for MFC, Visual Basic, and
other frameworks that have the concept of an updateable recordset.

I have tested extended scrolling, updates, deletes, and appends with
VC5.0 using their CRecordset in a snapshot mode (dynasets are not
supported).  It works well.  It transforms the positioned SQL statements
(which the backend does not support) coming from MFC into "searched
update" statements, which the backend accepts.  The default for the
CRecordset is to load the odbc cursor library, unless you tell it not to
when constructing a CDatabase object.

The "Use Declare/Fetch" option does not matter as much anymore, since
the cursor library gets in the middle of the driver manager and driver,
and supports the additional functionality, such as an updateable, static
cursor.
It does matter somewhat, in terms of efficiency, though, since the odbc
cursor library caches the data in its own memory and disk files.  If you
have the Use Declare/fetch option checked, it will be more efficient on
large result sets, since the driver will only cache 100 rows, while the
cursor library caches everything.  If you dont check the option, the
driver will also cache the entire result set.

For more information about the odbc cursor library, there is an appendix
about it in the odbc programmer's reference guide and in the online help
with VC.

As always, feedback is appreciated.  I.E., if it works for you, that
would be good feedback to send, as well as any problems of course.

Byron



version.txt           date:  5/28/98             version:  06.30.0243
---------------------------------------------------------------------
This file describes changes and or fixes since the last update.


NEW FEATURES:

1. Allow driver to work with odbc cursor library.  This involved adding the
   API functions SQLGetCursorName and SQLSetCursorName.  The odbc cursor
   library adds the ability to use static cursors, positioned update, extended
   fetches, block cursors, etc.  Successfully tested CRecordset (add, update,
   delete, scroll) with MFC/VC5.0 in a snapshot mode.

   - Updatetable snashots are supported through the cursor library.
   - Readonly snapshots are supported by the driver if "Use Declare/Fetch" is unchecked.
   - ForwardOnly cursors are supported by both.
   - Dynasets are not supported by the driver or the odbc cursor library.


BUG_FIXES:

1. Fixed more incorrect info calls, ex. return a real value for
   MAX_TABLE_NAME_LEN, MAX_CURSOR_NAME_LEN, and MAX_COLUMN_NAME_LEN.
   These are important because some apps (i.e., mfc) don't understand
   "0" as being unlimited -- they take it as a literal value!
   Therefore, 32 is the size now being returned for these things, which
   is accurate.

OTHER:

1. Changed "Use Cursors" to "Use Declare/Fetch" on advanced driver options
   dialog box to avoid confusion with odbc scrollable cursors.

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