3rd:QDBM - Revision history

Thomas Linder Puls: Links

2013-06-02T23:12:50Z

Links

← Older revision		Revision as of 01:12, 3 June 2013
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	Mikio Hirabayashi has built a very nice API called 'QDBM'.		Mikio Hirabayashi has built a very nice API called 'QDBM'.

	http://~~qdbm.sourceforge~~.~~net/~~		http://fallabs.com/qdbm/

	~~see also http:/~~/qdbm~~.sourceforge.net~~/~~benchmark.pdf~~

	QDBM is well known in the Unix world, but has been ported to Win32. Practically, it is a disk-based Hashtable + Binary tree + inverted list package. QDBM offers many solutions called 'depot', 'curia', 'villa', 'odeum' and is well worth a look if you want to manage large amount of data.		QDBM is well known in the Unix world, but has been ported to Win32. Practically, it is a disk-based Hashtable + Binary tree + inverted list package. QDBM offers many solutions called 'depot', 'curia', 'villa', 'odeum' and is well worth a look if you want to manage large amount of data.

Gildas Menier at 13:03, 11 January 2008

2008-01-11T13:03:17Z

← Older revision		Revision as of 15:03, 11 January 2008
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	Written by Gildas Menier.		Written by Gildas Menier.

	For the management of key->values in Visual Prolog, you may use factsDB, chainDB or some sql based solution. Each solution has benefits and drawbacks~~. For some reasons, I had to find another solution~~.		For the management of key->values in Visual Prolog, you may use factsDB, chainDB or some sql based solution. Each solution has benefits and drawbacks.

	Mikio Hirabayashi has built a very nice API called 'QDBM'.		Mikio Hirabayashi has built a very nice API called 'QDBM'.
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	Using a collection of instances of the visual prolog class 'depot', you can manage a very large hashtable on disk.		Using a collection of instances of the visual prolog class 'depot', you can manage a very large hashtable on disk.

	~~I do not provide a full documentation since the real documentation can be found on the above web site.~~ Only the port of depot is functional in this lib.		Only the port of depot is functional in this lib.

	~~I tried to simplify the use~~ of ~~this lib as much as possible, and tried not~~ to ~~get too far away from~~ the original API syntax:		The provided set of predicates stays relatively close to the original API syntax:

	<vip>NewDepot = depot::new("dtest"), % create a depot db		<vip>NewDepot = depot::new("dtest"), % create a depot db
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	More predicates are provided. Please, have a look on the documentation of QDBM/depot and on the depot.pro file.		More predicates are provided. Please, have a look on the documentation of QDBM/depot and on the depot.pro file.

	The project doesn't include a copy of qdbm (because of the allowed posting size); ~~I encourage~~ you to download the most up-to-date version on the site above. It is provided under the GNU Lesser GPL.		The project doesn't include a copy of qdbm (because of the allowed posting size); you should download the most up-to-date version on the site above. It is provided under the GNU Lesser GPL.
	Just copy the three following files into your exe directory:		Just copy the three following files into your exe directory:

Kari Rastas: The article uses often the term I (writer) so the writers name is needed or the article has to be changed in a non personal "mode"

2008-01-09T08:04:45Z

The article uses often the term I (writer) so the writers name is needed or the article has to be changed in a non personal "mode"

← Older revision		Revision as of 10:04, 9 January 2008
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			Written by Gildas Menier.

	For the management of key->values in Visual Prolog, you may use factsDB, chainDB or some sql based solution. Each solution has benefits and drawbacks. For some reasons, I had to find another solution.		For the management of key->values in Visual Prolog, you may use factsDB, chainDB or some sql based solution. Each solution has benefits and drawbacks. For some reasons, I had to find another solution.

Thomas Linder Puls: copied from forum

2008-01-08T23:30:02Z

copied from forum

New page

For the management of key->values in Visual Prolog, you may use factsDB, chainDB or some sql based solution. Each solution has benefits and drawbacks. For some reasons, I had to find another solution.

Mikio Hirabayashi has built a very nice API called 'QDBM'.

http://qdbm.sourceforge.net/

see also http://qdbm.sourceforge.net/benchmark.pdf

QDBM is well known in the Unix world, but has been ported to Win32. Practically, it is a disk-based Hashtable + Binary tree + inverted list package. QDBM offers many solutions called 'depot', 'curia', 'villa', 'odeum' and is well worth a look if you want to manage large amount of data.

In the enclosed project, you'll find a small 'depot' wrapper for Visual Prolog.

The example creates 1.000.000 (key, values) and then ask for 1.000.000 keys at random. All the key/values are stored on disk in a single file.

Using a collection of instances of the visual prolog class 'depot', you can manage a very large hashtable on disk.

I do not provide a full documentation since the real documentation can be found on the above web site. Only the port of depot is functional in this lib.

I tried to simplify the use of this lib as much as possible, and tried not to get too far away from the original API syntax:

<vip>NewDepot = depot::new("dtest"), % create a depot db
NewDepot:dbopen("create"), % open it (create mode)
NewDepot:dbput_string(Key, Value), % put a key,value
NewDepot:dbclose(), % close the file</vip>

and you can access the db as follows:

<vip>ReadDepot = depot::new("dtest"), %
ReadDepot:dbopen("read"), % open it in read mode
Value = ReadDepot:dbget_string(Key), % tries to find the value for a key, fails if no value
ReadDepot:dbclose(), %</vip>

More predicates are provided. Please, have a look on the documentation of QDBM/depot and on the depot.pro file.

The project doesn't include a copy of qdbm (because of the allowed posting size); I encourage you to download the most up-to-date version on the site above. It is provided under the GNU Lesser GPL.
Just copy the three following files into your exe directory:

* libiconv-2.dll
* mgwz.dll
* qdbm.dll

you will find the package there:

http://qdbm.sourceforge.net/win/

Example project/download in [http://discuss.visual-prolog.com/viewtopic.php?t=6594 Discussion forum: (how to) deal with large amounts of (key,value)]