hb_dbDrop clarification

[Luigi Ferraris]

Hi guys,
I need a clarification as per subject. I'll assume to use rdd as parameter, but related with DBFNTX: give me a cent for this.

1st scenario.
There are (they exist) two files:path_filename.dbf and path_filename.ntx. I have used hb_DbDrop( path_filename.dbf, NIL, cRdd ).
It works fine: all files are removed.

2nd scenario.
There is (it exist) one file:path_filename.dbf. I have used hb_DbDrop( path_filename.dbf, NIL, cRdd ).
It works fine: the file is removed.

3rd scenario: I know can be considered strange, unusual... anyway
There is (it exists) one file:path_filename.ntx. I have used hb_DbDrop( path_filename.ntx, NIL, cRdd ).
It doesn't works: the file is not removed.

Is this the normal behaviour? I repeat: the third scenario can be unusual.

TIA
Luigi Ferraris

[Luigi Ferraris]

A little errata corrige (copy&paste error)

Il giorno giovedì 11 febbraio 2016 20:56:05 UTC+1, Luigi Ferraris ha scritto:

3rd scenario: I know can be considered strange, unusual... anyway
There is (it exists) one file:path_filename.ntx. I have used hb_DbDrop( path_filename.ntx, NIL, cRdd ).
It doesn't works: the file is not removed.

There is (it exists) one file:path_filename.ntx. I have used hb_DbDrop( path_filename.dbf, NIL, cRdd ).
take a look to the file extension.

TIA
Luigi

[Maurizio la Cecilia]

Hi Luigi,
I think that your third scenario needs a generic file deletion command/function.
dbDrop is a table based function and correctly ignore an index/memo file when not linked to a dbf.
Just my personal opinion.
--
Maurizio

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[Przemyslaw Czerpak]

Hi Luigi,

This is [hb_]dbDrop() syntax:

hb_dbDrop( <cTableName> [, <cOrdBagName>] ;
[, <cRDD>] [, <hConnection>] ) -> <lRemoved>

If you want to remove indexes then you should use:

hb_dbDrop( "mydbf", "myindex1", "DBFNTX" )
hb_dbDrop( "mydbf", "myindex2", "DBFNTX" )
...

If you want to remove table, memo file and production
indexes then you should use:

hb_dbDrop( "mydbf",, "DBFNTX" )

In all cases I suggest to not use file name extensions and
allow RDD to use default ones. Such code is portable and
can work with any RDDs. In generic code you can also ignore
3-rd parameter above - if "DBFNTX" is not given then default
RDD set by rddSetDefault() is used.

Please note that when you remove index you should also pass
table name. In case of DBF* RDDs it's ignored by some other
RDDs may need table name to find index, i.e. such situation
happens in SQL RDBMs. Passing index name as first parameter
to [hb_]dbDrop() is a programmer bug. Some RDDs may try to
open table just to locate index storage and they will report
table corruption error or table does not exists.

Similar syntax is used by [hb_]dbExists().

best regards,
Przemek

On Thu, 11 Feb 2016, Luigi Ferraris wrote:
> Hi guys,
> I need a clarification as per subject. I'll assume to use rdd as parameter,
> but related with DBFNTX: give me a cent for this.
>
> 1st scenario.
> There are (they exist) two files:path_filename.dbf and path_filename.ntx. I
> have used hb_DbDrop( path_filename.dbf, NIL, cRdd ).
> It works fine: all files are removed.
>
> 2nd scenario.
> There is (it exist) one file:path_filename.dbf. I have used hb_DbDrop(
> path_filename.dbf, NIL, cRdd ).
> It works fine: the file is removed.
>

> 3rd scenario: *I know can be considered strange, unusual... anyway*

> There is (it exists) one file:path_filename.ntx. I have used hb_DbDrop(
> path_filename.ntx, NIL, cRdd ).
> It doesn't works: the file is not removed.
>
> Is this the normal behaviour? I repeat: the third scenario can be unusual.
>
> TIA
> Luigi Ferraris
>

[Luigi Ferraris]

Il 12/02/2016 13.12, Przemyslaw Czerpak ha scritto:
> best regards,
> Przemek
and

Il 12/02/2016 12.45, Maurizio la Cecilia ha scritto:
> I think that your third scenario needs a generic file deletion
> command/function.

many thanks.

I will follow suggestions.
Regards
Luigi

[Przemyslaw Czerpak]

On Fri, 12 Feb 2016, Luigi Ferraris wrote:

Hi,

> Il 12/02/2016 12.45, Maurizio la Cecilia ha scritto:
> >I think that your third scenario needs a generic file deletion
> >command/function.
> many thanks.
>
> I will follow suggestions.

Just to clarify.
Using generic file io functions to delete index files is not
good idea for portable programs. If you know table name then
use:
hb_dbDrop( cTablePathName, cIndexPathName )
If you do not know table name then use:
hb_dbDrop( , cIndexPathName )

best regards,
Przemek

[Maurizio la Cecilia]

Thanks, Przemek.
I wasn't aware of all the hb_dbDrop() parameters.
Best regards.
--
Maurizio

[Luigi Ferraris]

Hi Przemek

Il giorno venerdì 12 febbraio 2016 13:48:50 UTC+1, druzus ha scritto:

If you do not know table name then use:
   hb_dbDrop( , cIndexPathName )

it seems this doesn't works as espected (do not remove index file ). I have used this workaround

FOR EACH cNtxName IN aListOfIndex
   IF hb_fileExists( <cDbfName> )
      hb_dbDrop( <cDbfName>, <cNtxName> )
   ELSE
      hb_vfErase( <cNtxName> )
   END IF
NEXT

I'm investingating more.
Luigi
 

[Luigi Ferraris]

Il 02/12/2016 18.34, Luigi Ferraris ha scritto:

it seems this doesn't works as espected (do not remove index file ). I have used this workaround

FOR EACH cNtxName IN aListOfIndex
   IF hb_fileExists( <cDbfName> )
      hb_dbDrop( <cDbfName>, <cNtxName> )
   ELSE
      hb_vfErase( <cNtxName> )
   END IF
NEXT

lost a piece of code, sorry:

FOR EACH cNtxName IN aListOfIndex
   IF hb_fileExists( <cDbfName> )
      hb_dbDrop( <cDbfName>, <cNtxName> )
   ELSE
      hb_vfErase( <cNtxName> )
   END IF
NEXT

hb_dbDrop( <cDbfName> )

else .dbf is not removed

Luigi