1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="Content-Style-Type" content="text/css" />
<link rel="contents" href="./" />
<link rev="made" href="mailto:mikio@fallabs.com" />
<title>villa (QDBM for Ruby)</title>
<style type="text/css">html { margin: 0em 0em; padding 0em 0em; background: #eeeeee none; }
body { background-color: #eeeeee; color: #111111; padding: 1.5em 2em; margin: 0em 0em;
border-left: double 3.0em #eedddd; border-right: solid 1.0em #eedddd;
font-style: normal; font-weight: normal; font-family: serif; }
h1 { margin-top: 0.8em; margin-bottom: 1.3em; font-weight: bold; font-family: sans-serif; }
h2 { margin-top: 1.8em; margin-bottom: 1.1em; font-weight: bold; font-family: sans-serif; }
h3 { margin-top: 1.8em; margin-bottom: 0.8em; font-weight: bold; font-family: sans-serif; }
p,ul,ol,dl { line-height: 140%; }
em { color: #111111; font-style: italic; font-weight: normal; font-family: serif; }
kbd { color: #111111; font-style: normal; font-weight: bold; font-family: monospace; }
a { color: #0022aa; text-decoration: none; }
a:hover { color: #0033ee; text-decoration: underline; }
a.head { color: #111111; text-decoration: none; }
.note { text-align: right; }
</style>
</head>
<body>
<div class="note">[<a href="index.html">Back</a>]</div>
<h1>API of villa</h1>
<hr />
<dl>
<dt><kbd>require 'villa'</kbd></dt>
<dd>
The library `villa' should be included in application codes.
An instance of the class `Villa' is used as a database handle.
`Villa' performs Mix-in of `Enumerable'.
Each method of `Villa' throws an exception of `Villa::EANY' or its sub classes when an error
occurs: `Villa::ENOERR', `Villa::EFATAL', `Villa::EMODE', `Villa::EBROKEN', `Villa::EKEEP',
`Villa::ENOITEM', `Villa::EALLOC', `Villa::EMAP', `Villa::EOPEN', `Villa::ECLOSE',
`Villa::ETRUNC', `Villa::ESYNC', `Villa::ESTAT', `Villa::ESEEK', `Villa::EREAD',
`Villa::EWRITE', `Villa::ELOCK', `Villa::EUNLINK', `Villa::EMKDIR', `Villa::ERMDIR' and
`Villa::EMISC'.
</dd>
</dl>
<dl>
<dt><kbd>villa = Villa::new(name, omode, cmode)</kbd></dt>
<dd>
Constructor: Get a database handle.
`name' specifies the name of a database file.
`omode' specifies the connection mode: `Villa::OWRITER' as a writer, `Villa::OREADER' as a
reader. If the mode is `Villa::OWRITER', the following may be added by bitwise or:
`Villa::OCREAT', which means it creates a new database if not exist, `Villa::OTRUNC', which
means it creates a new database regardless if one exists, `Villa::OZCOMP', which means
leaves in the database are compressed with ZLIB, `Villa::OYCOMP', which means leaves in the
database are compressed with LZO, `Villa::OXCOMP', which means leaves in the database are
compressed with BZIP2. Both of `Villa::OREADER' and `Villa::OWRITER' can be added to by
bitwise or: `Villa::ONOLCK', which means it opens a database file without file locking, or
`Villa::OLCKNB', which means locking is performed without blocking. If it is omitted,
`Villa::OREADER' is specified.
`cmode' specifies the comparing function: `Villa::CMPLEX' comparing keys in lexical order,
`Villa::CMPDEC' comparing keys as decimal strings, `Villa::CMPOBJ' comparing keys as
serialized objects implementing the method `<=>'. The comparing function should be kept
same in the life of a database. If `Villa::CMPOBJ' is used, such methods as `put', `out',
`get' and so on can treat not only instances of `String' but also any serializable and
comparable object.
If so, objects being stored are serialized and objects being retrieved are deserialized.
The return value is the database handle.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
If a block parameter is given, this method works as an iterator. A database handle is
opened and passed via the first argument of the block. The database handle is surely
closed when the block is over.
While connecting as a writer, an exclusive lock is invoked to the database file.
While connecting as a reader, a shared lock is invoked to the database file. The thread
blocks until the lock is achieved. `Villa::OZCOMP', `Villa::OYCOMP', and `Villa::OXCOMP'
are available only if QDBM was built each with ZLIB, LZO, and BZIP2 enabled. If
`Villa::ONOLCK' is used, the application is responsible for exclusion control.
</dd>
</dl>
<dl>
<dt><kbd>villa = Villa::open(name, omode, cmode)</kbd></dt>
<dd>
Constructor: An alias of `new'.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.close()</kbd></dt>
<dd>
Method: Close the database handle.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
Because the region of a closed handle is released, it becomes impossible to use the handle.
Updating a database is assured to be written when the handle is closed. If a writer opens
a database but does not close it appropriately, the database will be broken. If the
transaction is activated and not committed, it is aborted.
</dd>
</dl>
<dl>
<dt><kbd>villa.silent = bool</kbd></dt>
<dd>
Method: Set the flag whether to repress frequent exceptions.
The return value is the assigned value.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.put(key, val, dmode)</kbd></dt>
<dd>
Method: Store a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
`val' specifies a value. Although it must be an instance of String, binary data is okey.
`dmode' specifies behavior when the key overlaps, by the following values: `Villa::DOVER',
which means the specified value overwrites the existing one, `Villa::DKEEP', which means the
existing value is kept, `Villa::DCAT', which means the specified value is concatenated at the
end of the existing value, `Villa::DDUP', which means duplication of keys is allowed and the
specified value is added as the last one, `Villa::DDUPR', which means duplication of keys is
allowed and the specified value is added as the first one. If it is omitted, `Villa::DOVER'
is specified.
The return value is always true. However, if the silent flag is true and replace is
cancelled, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or replace
is cancelled.
The cursor becomes unavailable due to updating database.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.store(key, val)</kbd></dt>
<dd>
Method: An alias of `put'.
</dd>
</dl>
<dl>
<dt><kbd>villa[key] = val</kbd></dt>
<dd>
Method: An alias of `put'.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.out(key)</kbd></dt>
<dd>
Method: Delete a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds.
When the key of duplicated records is specified, the value of the first record of the same
key is selected. The cursor becomes unavailable due to updating database.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.delete(key)</kbd></dt>
<dd>
Method: An alias of `out'.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.clear()</kbd></dt>
<dd>
Method: Delete all records.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.get(key)</kbd></dt>
<dd>
Method: Retrieve a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
The return value is an instance of the value of the corresponding record. If the silent flag
is true and no record corresponds, nil is returned instead of exception.
When the key of duplicated records is specified, the first record of the same key is
deleted.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.fetch(key, defval)</kbd></dt>
<dd>
Method: Retrieve a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
`defval' specifies the default value used when no record corresponds. If it is omitted, nil
is specified.
The return value is an instance of the value of the corresponding record, or the default
value if no record corresponds.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>str = villa[key]</kbd></dt>
<dd>
Method: An alias of `fetch'.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.vsiz(key)</kbd></dt>
<dd>
Method: Get the size of the value of a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
The return value is the size of the value of the corresponding record. If the silent flag
is true and no record corresponds, -1 is returned instead of exception. If multiple records
correspond, the size of the first is returned.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.vnum(key)</kbd></dt>
<dd>
Method: Get the number of records corresponding a key.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
The return value is the size of the value of the corresponding record. If no record
corresponds, 0 is returned.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curfirst()</kbd></dt>
<dd>
Method: Move the cursor to the first record.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or there is
no record in the database.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curlast()</kbd></dt>
<dd>
Method: Move the cursor to the last record.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or there is
no record in the database.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curprev()</kbd></dt>
<dd>
Method: Move the cursor to the previous record.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or there is
no previous record.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curnext()</kbd></dt>
<dd>
Method: Move the cursor to the next record.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or there is
no next record.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curjump(key, jmode)</kbd></dt>
<dd>
Method: Move the cursor to a position around a record.
`key' specifies a key. Although it must be an instance of String, binary data is okey.
`jmode' specifies detail adjustment: `Villa::JFORWARD', which means that the cursor is set
to the first record of the same key and that the cursor is set to the next substitute if
completely matching record does not exist, `Villa::JBACKWARD', which means that the cursor
is set to the last record of the same key and that the cursor is set to the previous
substitute if completely matching record does not exist. If it is omitted, `Villa::JFORWARD'
is specified.
The return value is always true. However, if the silent flag is true and no record
corresponds, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or there is
no record corresponding the condition.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.curkey()</kbd></dt>
<dd>
Method: Get the key of the record where the cursor is.
The return value is the key of the corresponding record. If the silent flag is true and no
record corresponds, nil is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds to the cursor.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.curval()</kbd></dt>
<dd>
Method: Get the value of the record where the cursor is.
The return value is the value of the corresponding record. If the silent flag is true and no
record corresponds, nil is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds to the cursor.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curput(val, cpmode);</kbd></dt>
<dd>
Method: Insert a record around the cursor.
`val' specifies a value. Although it must be an instance of String, binary data is okey.
`cpmode' specifies detail adjustment: `Villa::CPCURRENT', which means that the value of the
current record is overwritten, `Villa::CPBEFORE', which means that a new record is inserted
before the current record, `Villa::CPAFTER', which means that a new record is inserted after
the current record. If it is omitted, `Villa::CPCURRENT' is specified.
The return value is always true. However, if the silent flag is true and no record
corresponds to the cursor, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds to the cursor.
After insertion, the cursor is moved to the inserted record.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.curout();</kbd></dt>
<dd>
Method: Delete the record where the cursor is.
The return value is always true. However, if the silent flag is true and no record
corresponds to the cursor, false is returned instead of exception.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds to the cursor.
After deletion, the cursor is moved to the next record if possible.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.settuning(lrecmax, nidxmax, lcnum, ncnum)</kbd></dt>
<dd>
Method: Set the tuning parameters for performance.
`lrecmax' specifies the max number of records in a leaf node of B+ tree. If it is not more
than 0, the default value is specified.
`nidxmax' specifies the max number of indexes in a non-leaf node of B+ tree. If it is not
more than 0, the default value is specified.
`lcnum' specifies the max number of caching leaf nodes. If it is not more than 0, the
default value is specified.
`ncnum' specifies the max number of caching non-leaf nodes. If it is not more than 0, the
default value is specified.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
The default setting is equivalent to `vlsettuning(49, 192, 1024, 512)'. Because tuning
parameters are not saved in a database, you should specify them every opening a database.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.sync()</kbd></dt>
<dd>
Method: Synchronize updating contents with the file and the device.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
This method is useful when another process uses the connected database file. This method
should not be used while the transaction is activated.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.optimize()</kbd></dt>
<dd>
Method: Optimize the database.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
In an alternating succession of deleting and storing with overwrite or concatenate,
dispensable regions accumulate. This method is useful to do away with them. This method
should not be used while the transaction is activated.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.fsiz()</kbd></dt>
<dd>
Method: Get the size of the database file.
The return value is the size of the database file.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
Because of the I/O buffer, the return value may be less than the real size.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.rnum()</kbd></dt>
<dd>
Method: Get the number of the records stored in the database.
The return value is the number of the records stored in the database.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.length()</kbd></dt>
<dd>
Method: An alias of `rnum'.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.size()</kbd></dt>
<dd>
Method: An alias of `rnum'.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.writable()</kbd></dt>
<dd>
Method: Check whether the database handle is a writer or not.
The return value is true if the handle is a writer, false if not.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.fatalerror()</kbd></dt>
<dd>
Method: Check whether the database has a fatal error or not.
The return value is true if the database has a fatal error, false if not.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.tranbegin()</kbd></dt>
<dd>
Method: Begin the transaction.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
If a thread is already in the transaction, the other threads block until the prius is out
of the transaction. Only one transaction can be activated with a database handle at the
same time.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.trancommit()</kbd></dt>
<dd>
Method: Commit the transaction.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
Updating a database in the transaction is fixed when it is committed successfully. Any
other thread except for the one which began the transaction should not call this method.
</dd>
</dl>
<dl>
<dt><kbd>bool = villa.tranabort()</kbd></dt>
<dd>
Method: Abort the transaction.
The return value is always true.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
Updating a database in the transaction is discarded when it is aborted. The state of the
database is rollbacked to before transaction. Any other thread except for the one which
began the transaction should not call this method.
</dd>
</dl>
<dl>
<dt><kbd>villa.transaction() do ... end</kbd></dt>
<dd>
Iterator Method: Perform an iterator block in the transaction.
The specified iterator block is performed in the transaction. If the block returns true,
the transaction is committed. If the block returns false or raises any exception, the
transaction is aborted.
</dd>
</dl>
<dl>
<dt><kbd>villa.each() do |key, val| ... end</kbd></dt>
<dd>
Iterator Method: Iterate a process with a pair of a key and a value of each record.
</dd>
</dl>
<dl>
<dt><kbd>villa.each_pair() do |key, val| ... end</kbd></dt>
<dd>
Iterator Method: An alias of `each'.
</dd>
</dl>
<dl>
<dt><kbd>villa.each_key() do |key| ... end</kbd></dt>
<dd>
Iterator Method: Iterate a process with a key of each record.
</dd>
</dl>
<dl>
<dt><kbd>villa.each_value() do |val| ... end</kbd></dt>
<dd>
Iterator Method: Iterate a process with a value of each record.
</dd>
</dl>
<dl>
<dt><kbd>ary = villa.keys()</kbd></dt>
<dd>
Method: Get an array of all keys.
The return value is an array of all keys.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>ary = villa.values()</kbd></dt>
<dd>
Method: Get an array of all values.
The return value is an array of all values.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.index(val)</kbd></dt>
<dd>
Method: Retrieve a record with a value.
`val' specifies a value. Although it must be an instance of String, binary data is okey.
The return value is the key of the record with the specified value.
An exception of `Villa::EANY' or its sub classes is thrown if an error occurs or no record
corresponds.
If two or more records correspond, the first found record is selected.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.to_int()</kbd></dt>
<dd>
Method: An alias of `rnum'.
</dd>
</dl>
<dl>
<dt><kbd>num = villa.to_i()</kbd></dt>
<dd>
Method: An alias of `to_int'.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.to_str()</kbd></dt>
<dd>
Method: Get string standing for the instance.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.to_s()</kbd></dt>
<dd>
Method: An alias of `to_str'.
</dd>
</dl>
<dl>
<dt><kbd>ary = villa.to_ary()</kbd></dt>
<dd>
Method: Get an array of alternation of each pair of a key and a value.
</dd>
</dl>
<dl>
<dt><kbd>ary = villa.to_a()</kbd></dt>
<dd>
Method: An alias of `to_ary'.
</dd>
</dl>
<dl>
<dt><kbd>hash = villa.to_hash()</kbd></dt>
<dd>
Method: Get a hash storing all records.
</dd>
</dl>
<dl>
<dt><kbd>hash = villa.to_h()</kbd></dt>
<dd>
Method: An alias of `to_hash'.
</dd>
</dl>
<dl>
<dt><kbd>str = villa.inspect()</kbd></dt>
<dd>
Method: An alias of `to_str'.
</dd>
</dl>
<hr />
<div class="note">Generated by ./myrbdoc, 2010/08/05.</div>
</body>
</html>
|
