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1 =pod
2
3
4 =head1 NAME
5
6 Data::Storage - Interface for accessing various Storage implementations for Perl in an independent way
7
8
9 =head1 ABSTRACT ;-)
10
11 Data Storage
12
13 "Where is the wisdom? Lost in the knowledge.
14 Where is the knowledge? Lost in the information."
15 - T.S. Eliot
16
17 "Where is the information? Lost in the data.
18 Where is the data? Lost in the #@$%?!& database."
19 - Joe Celko
20
21
22 from: MacPerl: Power and Ease - Chapter 15
23 url: http://www.macperl.com/ptf_book/r/MP/330.Data_Storage.html
24
25
26 =head1 INTENTIONS
27
28 - should encapsulate Tangram, DBI, DBD::CSV and LWP:: to access them in an unordinary (more convenient) way ;)
29 - introduce a generic layered structure, refactor *SUBLAYER*-stuff, make (e.g.) this possible:
30 Perl Data::Storage[DBD::CSV] -> Perl LWP:: -> Internet HTTP/FTP/* -> Host Daemon -> csv-file
31 - provide generic synchronization mechanisms across arbitrary/multiple storages based on ident/checksum
32 maybe it's possible to have schema-, structural- and semantical modifications synchronized???
33 - might be similar to http://sourceforge.net/projects/perl-repository
34
35
36 =head1 SYNOPSIS
37
38 =head2 ACCESS
39
40 # connect to LDAP
41 my $ldapLocator = Data::Storage::Locator->new(
42 ldap => {
43 type => "NetLDAP",
44 dsn => "ldap:host=192.168.10.150;binddn='cn=root, o=netfrag.org, c=de';pass=secret",
45 basedn => "o=netfrag.org, c=de",
46 want_transactions => 0,
47 syncable => 1,
48 },
49 );
50 my $ldapStorage = Data::Storage->new($ldapLocator);
51 $ldapStorage->connect();
52
53 # connect to MAPI
54 my $mapiLocator = Data::Storage::Locator->new(
55 outlook => {
56 type => "MAPI",
57 showProfileChooser => $self->{config}->get("mapi_showProfileChooser"),
58 ProfileName => $self->{config}->get("mapi_ProfileName"),
59 ProfilePass => $self->{config}->get("mapi_ProfilePass"),
60 syncable => 1,
61 },
62 );
63 my $mapiStorage = Data::Storage->new($mapiLocator);
64 $mapiStorage->connect();
65
66
67 =head2 SYNCHRONIZATION
68
69 This functionality is (in the meanwhile) provided by the Data::Transfer::Sync module.
70
71 =head3 proposal V1
72
73 my $nodemapping = {
74 'LangText' => 'langtexts.csv',
75 'Currency' => 'currencies.csv',
76 'Country' => 'countries.csv',
77 };
78
79 my $propmapping = {
80 'LangText' => [
81 [ 'source:lcountrykey' => 'target:country' ],
82 [ 'source:lkey' => 'target:key' ],
83 [ 'source:lvalue' => 'target:text' ],
84 ],
85 'Currency' => [
86 [ 'source:ckey' => 'target:key' ],
87 [ 'source:cname' => 'target:text' ],
88 ],
89 'Country' => [
90 [ 'source:ckey' => 'target:key' ],
91 [ 'source:cname' => 'target:text' ],
92 ],
93 };
94
95 s ub syncResource {
96
97 my $self = shift;
98 my $node_source = shift;
99 my $mode = shift;
100 my $opts = shift;
101
102 $mode ||= '';
103 $opts->{erase} ||= 0;
104
105 $logger->info( __PACKAGE__ . "->syncResource( node_source $node_source mode $mode erase $opts->{erase} )");
106
107 # resolve metadata for syncing requested resource
108 my $node_target = $nodemapping->{$node_source};
109 my $mapping = $propmapping->{$node_source};
110
111 if (!$node_target || !$mapping) {
112 # loggger.... "no target, sorry!"
113 print "error while resolving resource metadata", "\n";
114 return;
115 }
116
117 if ($opts->{erase}) {
118 $self->_erase_all($node_source);
119 }
120
121 # create new sync object
122 my $sync = Data::Transfer::Sync->new(
123 storages => {
124 L => $self->{storage}->{backend},
125 R => $self->{storage}->{resources},
126 },
127 id_authorities => [qw( L ) ],
128 checksum_authorities => [qw( L ) ],
129 write_protected => [qw( R ) ],
130 verbose => 1,
131 );
132
133 # sync
134 # todo: filter!?
135 $sync->syncNodes( {
136 direction => $mode, # | +PUSH | +PULL | -FULL | +IMPORT | -EXPORT
137 method => 'checksum', # | -timestamp | -manual
138 source => "L:$node_source",
139 source_ident => 'storage_method:id',
140 source_exclude => [qw( id cs )],
141 target => "R:$node_target",
142 target_ident => 'property:oid',
143 mapping => $mapping,
144 } );
145
146 }
147
148 =head3 proposal V2
149
150 # create a new synchronization object
151 my $sync = Data::Transfer::Sync->new( 'sync_version' => $sync_version, __parent => $self );
152
153 # configure the synchronization-object
154 $sync->configure(
155 source => {
156 storage => {
157 handle => $mapiStorage,
158 #isIdentAuthority => 1,
159 #isChecksumAuthority => 1,
160 #writeProtected => 1,
161 },
162 },
163 target => {
164 storage => {
165 handle => $ldapStorage,
166 #idAuthority => 1,
167 #isChecksumAuthority => 1,
168 #isWriteProtected => 0,
169 },
170 },
171 verbose => 1,
172 );
173
174
175 =head2 NOTE
176
177 This module heavily relies on DBI and Tangram, but adds a lot of additional bugs and quirks.
178 Please look at their documentation and/or this code for additional information.
179
180
181 =head1 REQUIREMENTS
182
183 For full functionality:
184 DBI from CPAN
185 DBD::mysql from CPAN
186 Tangram 2.04 from CPAN (hmmm, 2.04 won't do in some cases)
187 Tangram 2.05 from http://... (2.05 seems okay but there are also additional patches from our side)
188 Class::Tangram from CPAN
189 DBD::CSV from CPAN
190 MySQL::Diff from http://adamspiers.org/computing/mysqldiff/
191 ... and all their dependencies
192
193
194 =head1 DESCRIPTION
195
196 =head2 Data::Storage
197
198 Data::Storage is a module for accessing various "data structures / kinds of structured data" stored inside
199 various "data containers".
200 We tried to use the AdapterPattern to implement a wrapper-layer around known CPAN modules.
201 (e.g. DBI, Tangram, XML::Simple)
202 References:
203 - http://c2.com/cgi/wiki?AdapterPattern
204 - http://home.earthlink.net/~huston2/dp/adapter.html
205
206 =head2 Why?
207
208 You will get a better code-structure (not bad for later maintenance) in growing Perl code projects,
209 especially when using multiple database connections at the same time.
210 You will be able to switch between different _kinds_ of implementations used for storing data.
211 Your code will use the very same API to access these storage layers.
212 ... implementation has to be changed for now
213 Maybe you will be able to switch "on-the-fly" without changing any bits in code in the future....
214 ... but that's not the focus
215
216 =head2 What else?
217
218 Having this, we were able to do implement a generic data synchronization module more easy,
219 please look at Data::Transfer.
220
221
222 =head1 AUTHORS / COPYRIGHT
223
224 The Data::Storage module is Copyright (c) 2002-2004 Andreas Motl.
225 All rights reserved.
226 Mail to <andreas.motl (at) ilo.de> for improvements and suggestions.
227
228 You may distribute it under the terms of either the GNU General Public
229 License or the Artistic License, as specified in the Perl README file.
230
231 =head1 CONTRIBUTORS
232
233 Sebastian Utz <su (at) rotamente.com>
234
235 =head1 ACKNOWLEDGEMENTS
236
237 Larry Wall for Perl, Tim Bunce for DBI, Jean-Louis Leroy for Tangram and Set::Object,
238 Sam Vilain for Class::Tangram, Jochen Wiedmann and Jeff Zucker for DBD::CSV & Co.,
239 Adam Spiers for MySQL::Diff and all contributors.
240
241 =head1 SUPPORT / WARRANTY
242
243 Data::Storage is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.
244
245
246 =head1 TODO
247
248 o interface with Jeff Zucker's AnyData:: modules, e.g. AnyData::Storage::RAM
249 o what about DBD::RAM? (DBD::RAM - a DBI driver for files and data structures)
250 o use DBD::Proxy!
251 o what about DBIx::AnyDBD?
252 o enhance schema information:
253 - DBIx::SystemCatalog
254 - DBIx::SystemCatalog::MSSQL?
255 - Data::Reporter
256
257
258 =head2 BUGS
259
260 "DBI-Error [Tangram]: DBD::mysql::st execute failed: Unknown column 't1.requestdump' in 'field list'"
261
262 ... occours when operating on object-attributes not introduced yet:
263 this should be detected and appended/replaced through:
264 "Schema-Error detected, maybe (just) an inconsistency.
265 Please check if your declaration in schema-module "a" matches structure in database "b" or try to run"
266 db_setup.pl --dbkey=import --action=deploy
267
268
269 Compare schema (structure diff) with database ...
270
271 ... when issuing "db_setup.pl --dbkey=import --action=deploy"
272 on a database with an already deployed schema, use an additional "--update" then
273 to lift the schema inside the database to the current declared schema.
274 You will have to approve removals and changes on field-level while
275 new objects and new fields are introduced silently without any interaction needed.
276 In future versions there may be additional options to control silent processing of
277 removals and changes.
278 See this CRUD-table applying to the actions occouring on Classes and Class variables when deploying schemas,
279 don't mix this up with CRUD-actions on Objects, these are already handled by (e.g.) Tangram itself.
280 Classes:
281 C create -> yes, handled automatically
282 R retrieve -> no, not subject of this aspect since it is about deployment only
283 U update -> yes, automatically for Class meta-attributes, yes/no for Class variables (look at the rules down here)
284 D delete -> yes, just by user-interaction
285 Class variables:
286 C create -> yes, handled automatically
287 R retrieve -> no, not subject of this aspect since it is about deployment only
288 U update -> yes, just by user-interaction; maybe automatically if it can be determined that data wouldn't be lost
289 D delete -> yes, just by user-interaction
290
291 It's all about not to be able to loose data simply while this is in pre-alpha stage.
292 And loosing data by being able to modify and redeploy schemas easily is definitely quite easy.
293
294 As we can see, creations of Classes and new Class variables is handled
295 automatically and this is believed to be the most common case under normal circumstances.
296
297
298 =head2 FEATURES
299
300 - Get this stuff together with UML (Unified Modeling Language) and/or standards from ODMG.
301 - Make it possible to load/save schemas in XMI (XML Metadata Interchange),
302 which seems to be most commonly used today, perhaps handle objects with OIFML.
303 Integrate/bundle this with a web-/html-based UML modeling tool or
304 some other interesting stuff like the "Co-operative UML Editor" from Uni Darmstadt. (web-/java-based)
305 - Enable Round Trip Engineering. Keep code and diagrams in sync. Don't annoy/bother the programmers.
306 - Add support for some more handlers/locators to be able to
307 access the following standards/protocols/interfaces/programs/apis transparently:
308 + DBD::CSV (via Data::Storage::Handler::DBI)
309 (-) Text::CSV, XML::CSV, XML::Excel
310 - MAPI
311 - LDAP
312 - DAV (look at PerlDAV: http://www.webdav.org/perldav/)
313 - Mbox (use formail for seperating/splitting entries/nodes)
314 - Cyrus (cyrdeliver - what about cyrretrieve (export)???)
315 - use File::DiffTree, use File::Compare
316 - Hibernate
317 - "Win32::UserAccountDb"
318 - "*nix::UserAccountDb"
319 - .wab - files (Windows Address Book)
320 - .pst - files (Outlook Post Storage?)
321 - XML (e.g. via XML::Simple?)
322 - Move to t3, look at InCASE
323 - some kind of security layer for methods/objects
324 - acls (stored via tangram/ldap?) for functions, methods and objects (entity- & data!?)
325 - where are the hooks needed then?
326 - is Data::Storage & Co. okay, or do we have to touch the innards of DBI and/or Tangram?
327 - an attempt to start could be:
328 - 'sub getACLByObjectId($id, $context)'
329 - 'sub getACLByMethodname($id, $context)'
330 - 'sub getACLByName($id, $context)'
331 ( would require a kinda registry to look up these very names pointing to arbitrary locations (code, data, ...) )
332 - add more hooks and various levels
333 - better integrate introduced 'getObjectByGuid'-mechanism from Data::Storage::Handler::Tangram
334
335
336 =head3 LINKS / REFERENCES
337
338 Specs:
339 UML 1.3 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-06-08.pdf
340 XMI 1.1 Spec: http://cgi.omg.org/cgi-bin/doc?ad/99-10-02.pdf
341 XMI 2.0 Spec: http://cgi.omg.org/docs/ad/01-06-12.pdf
342 ODMG: http://odmg.org/
343 OIFML: http://odmg.org/library/readingroom/oifml.pdf
344
345 CASE Tools:
346 Rational Rose (commercial): http://www.rational.com/products/rose/
347 Together (commercial): http://www.oi.com/products/controlcenter/index.jsp
348 InCASE - Tangram-based Universal Object Editor
349 Sybase PowerDesigner: http://www.sybase.com/powerdesigner
350
351 UML Editors:
352 Fujaba (free, university): http://www.fujaba.de/
353 ArgoUML (free): http://argouml.tigris.org/
354 Poseidon (commercial): http://www.gentleware.com/products/poseidonDE.php3
355 Co-operative UML Editor (research): http://www.darmstadt.gmd.de/concert/activities/internal/umledit.html
356 Metamill (commercial): http://www.metamill.com/
357 Violet (university, research, education): http://www.horstmann.com/violet/
358 PyUt (free): http://pyut.sourceforge.net/
359 (Dia (free): http://www.lysator.liu.se/~alla/dia/)
360 UMLet (free, university): http://www.swt.tuwien.ac.at/umlet/index.html
361 Voodoo (free): http://voodoo.sourceforge.net/
362 Umbrello UML Modeller: http://uml.sourceforge.net/
363
364 UML Tools:
365 http://www.objectsbydesign.com/tools/umltools_byPrice.html
366
367 Further readings:
368 http://www.google.com/search?q=web+based+uml+editor&hl=en&lr=&ie=UTF-8&oe=UTF-8&start=10&sa=N
369 http://www.fernuni-hagen.de/DVT/Aktuelles/01FHHeidelberg.pdf
370 http://www.enhyper.com/src/documentation/
371 http://cis.cs.tu-berlin.de/Dokumente/Diplomarbeiten/2001/skinner.pdf
372 http://citeseer.nj.nec.com/vilain00diagrammatic.html
373 http://archive.devx.com/uml/articles/Smith01/Smith01-3.asp
374
375
376 =cut
377

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