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source: Dev/trunk/rdfapi/sparql/SparqlEngineDb/SqlGenerator.php @ 12

Last change on this file since 12 was 12, checked in by basvannuland, 14 years ago
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1	<?php
2	require_once RDFAPI_INCLUDE_DIR . 'sparql/SparqlVariable.php';
3	require_once RDFAPI_INCLUDE_DIR . 'sparql/SparqlEngineDb/TypeSorter.php';
4	require_once RDFAPI_INCLUDE_DIR . 'sparql/SparqlEngineDb/FilterGenerator.php';
5	require_once RDFAPI_INCLUDE_DIR . 'sparql/SparqlEngineDb/SqlGeneratorException.php';
6
7	/**
8	* Creates sql statements from a Query object
9	*
10	* @author Christian Weiske <cweiske@cweiske.de>
11	* @license http://www.gnu.org/licenses/lgpl.html LGPL
12	*
13	* @package sparql
14	*/
15	class SparqlEngineDb_SqlGenerator
16	{
17	public $query = null;
18
19	/**
20	* Determines which variables can be found
21	* in which SQL result column.
22	* @example
23	* array(
24	* '?person' => array('t1', 's'),
25	' '?p' => array('t1', 'p'),
26	* '?mbox' => array('t2', 'o')
27	* )
28	* Would express that variable ?person is the subject
29	* in result table t1, and ?mbox is the object in
30	* table t2.
31	*
32	* @see $arCreationMethods
33	*
34	* @internal The array is created in createSql()
35	* and used in convertFromDbResult().
36	*
37	* @var array
38	*/
39	public $arVarAssignments = array();
40
41	/**
42	* Array of variable name => table.col assignments
43	* for all variables used in the query not only
44	* the ones that shall be returned.
45	*
46	* @example
47	* array(
48	* '?person' => 't0.subject'
49	* )
50	*
51	* @var array
52	*/
53	public $arUsedVarAssignments = array();
54
55	/**
56	* Array of arrays that contain all variable names
57	* which are to be found in the result of
58	* an sql statement in a union.
59	*
60	* @example
61	* array(
62	* 0 => array(
63	* '?person' => 's',
64	* '?p' => 'o'
65	* ),
66	* 1 => array(
67	* '?person' => 's',
68	* '?mbox' => 'o'
69	* )
70	* )
71	*
72	* @var array
73	*/
74	public $arUnionVarAssignments = array();
75
76	/**
77	* Which variables have been used as which type?
78	* key is variable name, value is an array of
79	* max. three keys (s, p, o)
80	*
81	* @example
82	* array(
83	* '?person' => array(
84	* 's' => true
85	* ),
86	* '?mbox' => array(
87	* 'o' => true
88	* )
89	* )
90	*
91	* @var array
92	*/
93	protected $arUsedVarTypes = array();
94
95	/**
96	* Array with placeholders of prepared statements variables.
97	* key is the variable name (without "??"), value is the
98	* placeholder.
99	* @var array
100	*/
101	protected $arPlaceholders = array();
102
103	/**
104	* Column names for subjects, predicates and
105	* objects for easy access via their character
106	* names (spo).
107	*
108	* @var array
109	*/
110	public static $arTableColumnNames = array(
111	's' => array(
112	'value' => 'subject',
113	'is' => 'subject_is'
114	),
115	'p' => array(
116	'value' => 'predicate'
117	),
118	'o' => array(
119	'value' => 'object',
120	'is' => 'object_is'
121	)
122	);
123
124	/**
125	* Current UNION part number
126	* @var int
127	*/
128	protected $nUnionCount = 0;
129
130	protected $nSqlVariableNameCount = 0;
131
132	/**
133	* Name of the statements table
134	*/
135	protected $tblStatements = 'statements';
136
137
138
139	public function __construct(Query $query, ADOConnection $dbConn, $arModelIds)
140	{
141	$this->query = $query;
142	$this->dbConn = $dbConn;
143	$this->arModelIds = $arModelIds;
144	}//public function __construct(Query $query, ADOConnection $dbConn, $arModelIds)
145
146
147
148	/**
149	* Creates an SQL query string from the given Sparql query object.
150	*
151	* @internal uses $query variable
152	*
153	* @return array Array of arrays of SQL query string parts: select, from and where
154	*
155	* @throws SparqlEngineDb_SqlGeneratorException If there is no variable in the result set.
156	*/
157	function createSql()
158	{
159	//var_dump($this->query);
160	$arSelect = array();
161	$arFrom = array();
162	$arWhere = array();
163
164	$strResultForm = $this->query->getResultForm();
165	$filterGen = new SparqlEngineDb_FilterGenerator($this);
166	switch ($strResultForm) {
167	case 'construct':
168	$arResultVars = $this->query->getConstructPatternVariables();
169	break;
170	default:
171	$arResultVars = $this->query->getResultVars();
172	break;
173	}
174
175	$this->nTableId = 0;
176	$this->nGraphPatternCount = 0;
177	$this->nUnionCount = 0;
178	$this->nUnionTriplePatternCount = 0;
179	$this->arUnionVarAssignments[0] = array();
180
181	foreach ($this->query->getResultPart() as $graphPattern) {
182	if ($graphPattern->isEmpty()) {
183	continue;
184	}
185	if ($graphPattern->getUnion() !== null) {
186	++$this->nUnionCount;
187	$this->nTableId = 0;
188	$this->nUnionTriplePatternCount = 0;
189	$this->nGraphPatternCount = 0;
190	$this->arUnionVarAssignments[$this->nUnionCount] = array();
191	}
192	$this->nTriplePatternCount = 0;
193	$arTriplePattern = $graphPattern->getTriplePatterns();
194	if ($arTriplePattern != null) {
195	foreach ($arTriplePattern as $triplePattern) {
196	list (
197	$arSelect[$this->nUnionCount][],
198	$arFrom [$this->nUnionCount][],
199	$arWhere [$this->nUnionCount][]
200	) =
201	$this->getTripleSql(
202	$triplePattern,
203	$graphPattern,
204	$arResultVars
205	);
206	++$this->nTableId;
207	++$this->nTriplePatternCount;
208	++$this->nUnionTriplePatternCount;
209	}
210	}
211	++$this->nGraphPatternCount;
212
213	}
214
215	//constraints extra. needed, since OPTIONAL parts are put after
216	// the current pattern while the constraint already refers to variables
217	// defined in there
218	$this->nGraphPatternCount = 0;
219	$this->nUnionCount = 0;
220	foreach ($this->query->getResultPart() as $graphPattern) {
221	if ($graphPattern->getUnion() !== null) {
222	++$this->nUnionCount;
223	}
224	$arConstraints = $graphPattern->getConstraints();
225	if ($arConstraints != null) {
226	foreach ($arConstraints as $constraint) {
227	$arWhere[$this->nUnionCount][count($arWhere[$this->nUnionCount]) - 1]
228	.= $filterGen->createFilterSql(
229	$constraint->getTree(),
230	$graphPattern->getOptional() !== null,
231	$this->nUnionCount
232	);
233	}
234	}
235	++$this->nGraphPatternCount;
236	}
237
238	$arSelect = $this->createEqualSelects($arSelect);
239	$arStrSelect = array();
240
241	switch ($strResultForm) {
242	case 'construct':
243	case 'describe':
244	$strSelectType = 'SELECT';
245	case 'select':
246	case 'select distinct':
247	if (!isset($strSelectType)) {
248	$strSelectType = $strResultForm;
249	}
250	foreach ($arSelect as $nUnionCount => $arSelectPart) {
251	$arSelectPart = self::removeNull($arSelectPart);
252	if (count($arSelectPart) == 0
253	\|\| (count($arSelectPart) == 1 && $arSelectPart[0] == '')) {
254	//test "test-1-07" suggests we return no rows in this case
255	//throw new SparqlEngineDb_SqlGeneratorException('No variable that could be returned.');
256	} else {
257	$arStrSelect[$nUnionCount] = strtoupper($strSelectType) . ' ' . implode(', ' , $arSelectPart);
258	}
259	}
260	break;
261
262	case 'ask':
263	case 'count':
264	$arStrSelect = array('SELECT COUNT(*) as count');
265	break;
266
267	default:
268	throw new SparqlEngineDb_SqlGeneratorException('Unsupported query type "' . $strResultForm . '"');
269	break;
270	}
271
272	$arSqls = array();
273	foreach ($arStrSelect as $nUnionCount => $arSelectPart) {
274	$arSqls[] = array(
275	'select' => $arStrSelect[$nUnionCount],
276	'from' => ' FROM ' . implode(' ' , self::removeNull($arFrom[$nUnionCount])),
277	'where' => ' WHERE ' . self::fixWhere(
278	implode(' ' , self::removeNull($arWhere[$nUnionCount]))
279	)
280	);
281	}
282	return $arSqls;
283	}//function createSql()
284
285
286
287	/**
288	* Creates some SQL statements from the given triple pattern
289	* array.
290	*
291	* @param QueryTriple $triple Array containing subject, predicate and object
292	* @param GraphPattern $graphPattern Graph pattern object
293	*
294	* @return array Array consisting of on array and two string values:
295	* SELECT, FROM and WHERE part
296	*/
297	function getTripleSql(QueryTriple $triple, GraphPattern $graphPattern, $arResultVars)
298	{
299	$arSelect = array();
300	$strFrom = null;
301	$strWhere = null;
302	$strWhereEquality = '';
303	$bWhereEqualitySubject = false;
304	$bWhereEqualityPredicate = false;
305	$bWhereEqualityObject = false;
306
307	$subject = $triple->getSubject();
308	$predicate = $triple->getPredicate();
309	$object = $triple->getObject();
310
311	$arRefVars = array();
312	$strTablePrefix = 't' . $this->nTableId;
313
314	/**
315	* SELECT part
316	* We do select only the columns we need for variables
317	*/
318	if (SparqlVariable::isVariable($subject)) {
319	if (isset($this->arUnionVarAssignments[$this->nUnionCount][$subject])) {
320	//already selected -> add equality check
321	$bWhereEqualitySubject = true;
322	$this->arUsedVarTypes[$subject]['s'] = true;
323	} else {
324	if (isset($this->arVarAssignments[$subject][0])) {
325	$strTablePrefix = $this->arVarAssignments[$subject][0];
326	}
327	$this->arVarAssignments[$subject] = array($strTablePrefix, 's');
328	$this->arUnionVarAssignments[$this->nUnionCount][$subject] = array($strTablePrefix, 's');
329	$this->arUsedVarTypes[$subject]['s'] = true;
330	if (self::isResultVar($subject, $arResultVars)) {
331	//new variable that needs to be selected
332	$arSelect[$subject] = $this->createVariableSelectArray(
333	's', $subject, $strTablePrefix
334	);
335	if (isset($this->arUsedVarAssignments[$subject])) {
336	$arRefVars[$subject] = $strTablePrefix . '.subject';
337	} else {
338	$this->arUsedVarAssignments[$subject] = $strTablePrefix . '.subject';
339	}
340	}
341	}
342	}
343
344	if (SparqlVariable::isVariable($predicate)) {
345	if (isset($this->arUnionVarAssignments[$this->nUnionCount][$predicate])) {
346	//already selected -> add equality check
347	$bWhereEqualityPredicate = true;
348	$this->arUsedVarTypes[$predicate]['p'] = true;
349	} else {
350	if (isset($this->arVarAssignments[$predicate][0])) {
351	$strTablePrefix = $this->arVarAssignments[$predicate][0];
352	}
353	$this->arVarAssignments[$predicate] = array($strTablePrefix, 'p');
354	$this->arUnionVarAssignments[$this->nUnionCount][$predicate] = array($strTablePrefix, 'p');
355	$this->arUsedVarTypes[$predicate]['p'] = true;
356	if (self::isResultVar($predicate, $arResultVars)) {
357	$arSelect[$predicate] = $this->createVariableSelectArray(
358	'p', $predicate, $strTablePrefix
359	);
360	if (isset($this->arUsedVarAssignments[$predicate])) {
361	$arRefVars[$predicate] = $strTablePrefix . '.predicate';
362	} else {
363	$this->arUsedVarAssignments[$predicate] = $strTablePrefix . '.predicate';
364	}
365	}
366	}
367	}
368
369	if (SparqlVariable::isVariable($object)) {
370	if (isset($this->arUnionVarAssignments[$this->nUnionCount][$object])) {
371	//already selected -> add equality check
372	$bWhereEqualityObject = true;
373	$this->arUsedVarTypes[$object]['o'] = true;
374	} else {
375	if (isset($this->arVarAssignments[$object][0])) {
376	$strTablePrefix = $this->arVarAssignments[$object][0];
377	}
378	$this->arVarAssignments[$object] = array($strTablePrefix, 'o');
379	$this->arUnionVarAssignments[$this->nUnionCount][$object] = array($strTablePrefix, 'o');
380	$this->arUsedVarTypes[$object]['o'] = true;
381	if (self::isResultVar($object, $arResultVars)) {
382	$arSelect[$object] = $this->createVariableSelectArray(
383	'o', $object, $strTablePrefix
384	);
385	if (isset($this->arUsedVarAssignments[$object])) {
386	$arRefVars[$object] = $strTablePrefix . '.object';
387	} else {
388	$this->arUsedVarAssignments[$object] = $strTablePrefix . '.object';
389	}
390	}
391	if (isset($this->query->varLanguages[$object])
392	&& $this->query->varLanguages[$object] !== null
393	) {
394	$strWhereEquality .=
395	' AND ' . $strTablePrefix . '.l_language = "'
396	. addslashes($this->query->varLanguages[$object]) . '"';
397	}
398	if (isset($this->query->varDatatypes[$object])
399	&& $this->query->varDatatypes[$object] !== null
400	) {
401	$strWhereEquality .=
402	' AND ' . $strTablePrefix . '.l_datatype = "'
403	. addslashes($this->query->varDatatypes[$object]) . '"';
404	}
405	}
406	}
407
408	/**
409	* WhereEquality - needs to be done now because strTablePrefix may change
410	*/
411	if ($bWhereEqualitySubject) {
412	$strWhereEquality .= ' AND ' . self::getSqlEqualityCondition(
413	array($strTablePrefix, 's'),
414	$this->arVarAssignments[$subject]
415	);
416	}
417	if ($bWhereEqualityPredicate) {
418	$strWhereEquality .= ' AND ' . self::getSqlEqualityCondition(
419	array($strTablePrefix, 'p'),
420	$this->arVarAssignments[$predicate]
421	);
422	}
423	if ($bWhereEqualityObject) {
424	$strWhereEquality .= ' AND ' . self::getSqlEqualityCondition(
425	array($strTablePrefix, 'o'),
426	$this->arVarAssignments[$object]
427	);
428	}
429
430
431	/**
432	* FROM part
433	*/
434	if ($this->nUnionTriplePatternCount == 0) {
435	//first FROM
436	$strFrom = $this->tblStatements . ' as ' . $strTablePrefix;
437	} else {
438	//normal join
439	if (count($this->arModelIds) == 1) {
440	$strFrom = 'LEFT JOIN ' . $this->tblStatements . ' as ' . $strTablePrefix
441	. ' ON t0.modelID = ' . $strTablePrefix . '.modelID';
442	} else if (count($this->arModelIds) > 1) {
443	$arIDs = array();
444	foreach ($this->arModelIds as $nId) {
445	$arIDs[] = $strTablePrefix . '.modelID = ' . intval($nId);
446	}
447	$strFrom = 'LEFT JOIN ' . $this->tblStatements . ' as ' . $strTablePrefix
448	. ' ON (' . implode(' OR ', $arIDs) . ')';
449	} else {
450	$strFrom = 'LEFT JOIN ' . $this->tblStatements . ' as ' . $strTablePrefix
451	. ' ON t0.modelID = ' . $strTablePrefix . '.modelID';
452	}
453
454	foreach ($arRefVars as $strRefVar => $strSqlVar) {
455	$strFrom .= ' AND ' . $this->arUsedVarAssignments[$strRefVar] . ' = ' . $strSqlVar;
456	}
457
458	if ($graphPattern->getOptional() !== null) {
459	$strFrom .= $this->getSqlCondition($subject , $strTablePrefix, 'subject')
460	. $this->getSqlCondition($predicate, $strTablePrefix, 'predicate')
461	. $this->getSqlCondition($object , $strTablePrefix, 'object')
462	. $strWhereEquality;
463	}
464	}
465
466
467	/**
468	* WHERE part
469	*/
470	if ($this->nUnionTriplePatternCount == 0) {
471	if (count($this->arModelIds) == 1) {
472	$strWhere = $strTablePrefix . '.modelID = ' . intval(reset($this->arModelIds));
473	} else if (count($this->arModelIds) > 1) {
474	$arIDs = array();
475	foreach ($this->arModelIds as $nId) {
476	$arIDs[] = $strTablePrefix . '.modelID = ' . intval($nId);
477	}
478	$strWhere = '(' . implode(' OR ', $arIDs) . ')';
479	} else {
480	//so that we can append an AND
481	$strWhere = '1';
482	}
483	}
484	if ($graphPattern->getOptional() === null \|\| $this->nGraphPatternCount == 0) {
485	$strWhere .= $this->getSqlCondition($subject , $strTablePrefix, 'subject')
486	. $this->getSqlCondition($predicate, $strTablePrefix, 'predicate')
487	. $this->getSqlCondition($object , $strTablePrefix, 'object')
488	. $strWhereEquality;
489	}
490
491	return array($arSelect, $strFrom, $strWhere);
492	}//function getTripleSql(QueryTriple $triple)
493
494
495
496
497	protected function createVariableSelectArray($chType, $varname, $strTablePrefix)
498	{
499	$var = $this->query->getResultVar($varname);
500	if ($var !== false) {
501	if ((string)$var != $varname) {
502	//copy over var assignments
503	$this->arVarAssignments[(string)$var] = $this->arVarAssignments[$varname];
504	}
505
506	//works on non-* only
507	$func = $var->getFunc();
508	if ($func != null) {
509	if ($func == 'datatype') {
510	if ($chType != 'o') {
511	throw new SparqlEngineDb_SqlGeneratorException(
512	'datatype() works on objects only'
513	);
514	}
515	return array(
516	$strTablePrefix . '.l_datatype as "' . $strTablePrefix . '.' . $this->getSqlVariableNameValue($var) . '"',
517	'"r"' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameIs($var) . '"',
518	'""' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameLanguage($var) . '"',
519	'""' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameDatatype($var) . '"',
520	);
521	} else if ($func == 'lang') {
522	if ($chType != 'o') {
523	throw new SparqlEngineDb_SqlGeneratorException(
524	'lang() works on objects only'
525	);
526	}
527	return array(
528	$strTablePrefix . '.l_language as "' . $strTablePrefix . '.' . $this->getSqlVariableNameValue($var) . '"',
529	'"l"' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameIs($var) . '"',
530	'""' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameLanguage($var) . '"',
531	'""' . ' as "' . $strTablePrefix . '.' . $this->getSqlVariableNameDatatype($var) . '"',
532	);
533	} else {
534	throw new SparqlEngineDb_SqlGeneratorException(
535	'Unsupported function for select "' . $func . '"'
536	);
537	}
538	}
539	}
540
541	switch ($chType) {
542	case 's':
543	return array(
544	$strTablePrefix . '.subject as "' . $strTablePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"',
545	$strTablePrefix . '.subject_is as "' . $strTablePrefix . '.' . $this->getSqlVariableNameIs($varname) . '"'
546	);
547	case 'p':
548	return array(
549	$strTablePrefix . '.predicate as "' . $strTablePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"'
550	);
551	case 'o':
552	return array(
553	$strTablePrefix . '.object as "' . $strTablePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"',
554	$strTablePrefix . '.object_is as "' . $strTablePrefix . '.' . $this->getSqlVariableNameIs($varname) . '"',
555	$strTablePrefix . '.l_language as "' . $strTablePrefix . '.' . $this->getSqlVariableNameLanguage($varname) . '"',
556	$strTablePrefix . '.l_datatype as "' . $strTablePrefix . '.' . $this->getSqlVariableNameDatatype($varname) . '"',
557	);
558	default:
559	throw new SparqlEngineDb_SqlGeneratorException(
560	'Unknown sentence type "' . $chType . "', one of (s,p,o) expected"
561	);
562	}
563	}//protected function createVariableSelectArray($chType, $value, $strTablePrefix)
564
565
566
567	/**
568	* Creates SELECT statements that have the same number of columns.
569	* Needed for UNIONs.
570	*
571	* @param array $arSelect Array of arrays.
572	* array(
573	* //for each union part one
574	* 0 => array(
575	* //foreach triple pattern
576	* 0 => array(
577	* '?person' => array(
578	* 't0.subject as "t0.subject"'
579	* )
580	* )
581	* )
582	* )
583	* @return array Array of SELECT strings
584	*/
585	protected function createEqualSelects($arSelect)
586	{
587	$arNewSelect = array();
588	if (count($arSelect) == 1) {
589	if ($arSelect[0] == array(array())) {
590	//ASK and COUNT
591	return array(array(''));
592	}
593
594	foreach ($arSelect[0] as $arTripleVars) {
595	$ar = array();
596	foreach ($arTripleVars as $arVarParts) {
597	$ar[] = implode(', ', $arVarParts);
598	}
599	if (count($ar) > 0) {
600	$arNewSelect[0][] = implode(', ', $ar);
601	}
602	}
603	return $arNewSelect;
604	}
605
606	$arVars = array();
607	foreach ($arSelect as $arUnionVars) {
608	foreach ($arUnionVars as $arTripleVars) {
609	$arVars = array_merge($arVars, array_keys($arTripleVars));
610	}
611	}
612	$arVars = array_unique($arVars);
613
614	foreach ($arSelect as $nUnionCount => $arUnionVars) {
615	$arSelectVars = array();
616	foreach ($arUnionVars as $arTripleVars) {
617	foreach ($arTripleVars as $strVar => $arVarParts) {
618	$arSelectVars[$strVar] = $arVarParts;
619	}
620	}
621
622	$ars = array();
623	foreach ($arVars as $strVar) {
624	if (isset($arSelectVars[$strVar])) {
625	$ar = $arSelectVars[$strVar];
626	$nCount = count($arSelectVars[$strVar]);
627	} else {
628	$ar = array();
629	$nCount = 0;
630	}
631
632	if ($nCount == 0) {
633	//nothing of this variable in this union part
634	$ar[] = 'NULL as '
635	. '"' . $this->arVarAssignments[$strVar][0] . '.' . $this->arVarAssignments[$strVar]['sql_value'] . '"';
636	}
637	if ((
638	isset($this->arUsedVarTypes[$strVar]['o'])
639	\|\| isset($this->arUsedVarTypes[$strVar]['s'])
640	) && $nCount < 2
641	) {
642	//it's a subject or object, but we don't want the type
643	$ar[] = 'NULL as '
644	. '"' . $this->arVarAssignments[$strVar][0] . '.' . $this->arVarAssignments[$strVar]['sql_is'] . '"';
645	}
646	if (isset($this->arUsedVarTypes[$strVar]['o']) && $nCount < 4) {
647	//it's a subject or object, but we don't want the type
648	if (isset($this->arVarAssignments[$strVar]['sql_lang'])) {
649	$strColLanguage = $this->arVarAssignments[$strVar]['sql_lang'];
650	} else {
651	$strColLanguage = 'dummyLang';
652	}
653	if (isset($this->arVarAssignments[$strVar]['sql_type'])) {
654	$strColDatatype = $this->arVarAssignments[$strVar]['sql_type'];
655	} else {
656	$strColDatatype = 'dummyType';
657	}
658	$ar[] = 'NULL as '
659	. '"' . $this->arVarAssignments[$strVar][0] . '.' . $strColLanguage . '"';
660	$ar[] = 'NULL as '
661	. '"' . $this->arVarAssignments[$strVar][0] . '.' . $strColDatatype . '"';
662	}
663	$ars[] = implode(', ', $ar);
664	}
665	$arNewSelect[$nUnionCount] = $ars;
666	}
667
668	return $arNewSelect;
669	}//protected function createEqualSelects($arSelect)
670
671
672
673	/**
674	* Creates an SQL statement that checks for the value
675	* of some subject/predicate/object
676	*
677	* @param mixed $bject subject\|predicate\|object
678	* @param string $strTablePrefix Table prefix (e.g. "t0")
679	* @param string $strType Type of $bject ('subject'\|'predicate'\|'object')
680	* @return string Part of the SQL query (prefixed with AND)
681	*/
682	function getSqlCondition($bject, $strTablePrefix, $strType)
683	{
684	if (is_string($bject)) {
685	if (SparqlVariable::isVariable($bject)) {
686	//variable?
687	if (self::isPreparedVariable($bject)) {
688	//no, not really
689	$value = $this->getPreparedVariablePlaceholder($bject);
690	} else {
691	//yes
692	return null;
693	}
694	} else {
695	$value = $this->dbConn->qstr($bject);
696	}
697	//literal
698	return ' AND ' . $strTablePrefix . '.' . $strType . ' = ' . $value;
699	}
700
701	if ($bject instanceof BlankNode) {
702	//Blank node
703	throw new SparqlEngineDb_SqlGeneratorException(
704	'FIXME: Querying for blank nodes not supported'
705	);
706
707	} else if ($bject instanceof Resource) {
708	//Resource
709	$r = ' AND ' . $strTablePrefix . '.' . $strType . ' = '
710	. $this->dbConn->qstr($bject->getURI());
711	if ($strType !== 'predicate') {
712	$r .= ' AND ' . $strTablePrefix . '.' . $strType . '_is ='
713	. ' "r"';
714	}
715	return $r;
716
717	} else if ($bject instanceof Literal) {
718	//Literal
719	//I'm doubling Filter code here, but what the hell
720	$strColDatatype = $strTablePrefix . '.l_datatype';
721	if ($bject->dtype == 'http://www.w3.org/2001/XMLSchema#integer'
722	\|\| $bject->dtype == 'http://www.w3.org/2001/XMLSchema#double'
723	) {
724	$strVariable = 'CAST(' . $strTablePrefix . '.' . $strType . ' AS DECIMAL(15,10))';
725	$strValue = $bject->getLabel();
726	} else {
727	$strVariable = $strTablePrefix . '.' . $strType;
728	$strValue = $this->dbConn->qstr($bject->getLabel());
729	}
730	$r = ' AND ' . $strVariable . ' = ' . $strValue;
731	if ($strType !== 'predicate') {
732	$r .= ' AND ' . $strTablePrefix . '.' . $strType . '_is ='
733	. ' "l"';
734	}
735
736	if ($strType == 'object') {
737	if ($bject->dtype == '' \|\| $bject->dtype == 'http://www.w3.org/2001/XMLSchema#string') {
738	//string
739	$r .= ' AND ('
740	. $strColDatatype . ' = ""'
741	. ' OR ' . $strColDatatype . ' = "http://www.w3.org/2001/XMLSchema#string"'
742	. ')';
743	} else {
744	$r .= ' AND ' . $strColDatatype . ' = "'
745	. $bject->dtype
746	. '"';
747	}
748	}
749
750	if ($bject->lang != '') {
751	$strColLanguage = $strTablePrefix . '.l_language';
752	$r .= ' AND ' . $strColLanguage . ' = '
753	. $this->dbConn->qstr($bject->lang);
754	}
755	return $r;
756
757	} else {
758	throw new SparqlEngineDb_SqlGeneratorException(
759	'Unsupported sentence part: ' . get_class($bject)
760	);
761	}
762	}//function getSqlCondition($bject, $strTablePrefix, $strType)
763
764
765
766	/**
767	* Checks if the sentence part (subject, predicate or object) in
768	* $arNew has the same content as $arOld.
769	* Required for queries like ":x ?a ?a" where predicate and object
770	* need to have the same value
771	*
772	* @param array $arNew array($strTablePrefix, $strType = s\|p\|o)
773	* @param array $arOld array($strTablePrefix, $strType = s\|p\|o)
774	* @return string
775	*/
776	protected static function getSqlEqualityCondition($arNew, $arOld)
777	{
778	$chTypeNew = $arNew[1]; $chTypeOld = $arOld[1];
779	$strTablePrefixNew = $arNew[0]; $strTablePrefixOld = $arOld[0];
780
781	if ($chTypeNew == 'p' \|\| $chTypeOld == 'p') {
782	//just check value
783	//FIXME: it might be I need to check for resource type in object and subject
784	return
785	$strTablePrefixNew . '.' . self::$arTableColumnNames[$chTypeNew]['value']
786	. ' = '
787	. $strTablePrefixOld . '.' . self::$arTableColumnNames[$chTypeOld]['value']
788	;
789	} else if ($chTypeNew == 's' \|\| $chTypeOld == 's') {
790	//check value and type
791	return
792	$strTablePrefixNew . '.' . self::$arTableColumnNames[$chTypeNew]['value']
793	. ' = '
794	. $strTablePrefixOld . '.' . self::$arTableColumnNames[$chTypeOld]['value']
795	. ' AND '
796	. $strTablePrefixNew . '.' . self::$arTableColumnNames[$chTypeNew]['is']
797	. ' = '
798	. $strTablePrefixOld . '.' . self::$arTableColumnNames[$chTypeOld]['is']
799	;
800	} else {
801	//two objects -> check everything
802	return
803	$strTablePrefixNew . '.object = ' . $strTablePrefixOld . '.object'
804	. ' AND '
805	. $strTablePrefixNew . '.object_is = ' . $strTablePrefixOld . '.object_is'
806	. ' AND '
807	. $strTablePrefixNew . '.l_language = ' . $strTablePrefixOld . '.l_language'
808	. ' AND '
809	. $strTablePrefixNew . '.l_datatype = ' . $strTablePrefixOld . '.l_datatype'
810	;
811	}
812	}//protected static function getSqlEqualityCondition($arNew, $arOld)
813
814
815
816	/**
817	* Checks if the given variable name is part of the result
818	* variables list.
819	* Needed since $arResultVars may contain "*" that captures all variables.
820	*
821	* @param string $strVar Variable name (e.g. "?p")
822	* @param array $arResultVars Array with result variables
823	* @return boolean true if it is a result variable
824	*/
825	protected static function isResultVar($strVar, &$arResultVars)
826	{
827	foreach ($arResultVars as $var) {
828	if ($var == '*') {
829	return true;
830	} else if ((is_string($var) && $var == $strVar)
831	\|\| (is_object($var) && $var->getVariable() == $strVar)) {
832	return true;
833	}
834	}
835	return false;
836	}//protected static function isResultVar($strVar, &$arResultVars)
837
838
839
840	/**
841	* Checks if the given variable is a replacement
842	* for a prepared statement.
843	*
844	* @return boolean
845	*/
846	public static function isPreparedVariable($bject)
847	{
848	return is_string($bject) && strlen($bject) >= 3
849	&& ($bject[0] == '?' \|\| $bject[0] == '$')
850	&& ($bject[1] == '?' \|\| $bject[1] == '$')
851	;
852	}//public static function isPreparedVariable($bject)
853
854
855
856	/**
857	* Returns a placeholder to be included in the sql statement.
858	* It will be replaced with a real prepared statement variable later on.
859	* Also adds it to the internal placeholder array.
860	*
861	* @param string $strVariable The variable to get a placeholder for
862	* @return string placeholder
863	*/
864	protected function getPreparedVariablePlaceholder($strVariable)
865	{
866	$strName = substr($strVariable, 2);
867	if (!isset($this->arPlaceholders[$strName])) {
868	$this->arPlaceholders[$strName] = '@$%_PLACEHOLDER_'
869	. count($this->arPlaceholders) . '_%$@';
870	}
871	return $this->arPlaceholders[$strName];
872	}//protected function getPreparedVariablePlaceholder($strVariable)
873
874
875
876	public function getPlaceholders()
877	{
878	return $this->arPlaceholders;
879	}//public function getPlaceholders()
880
881
882
883	public function getVarAssignments()
884	{
885	return $this->arVarAssignments;
886	}//public function getVarAssignments()
887
888
889
890	public function getUsedVarAssignments()
891	{
892	return $this->arUsedVarAssignments;
893	}//public function getUsedVarAssignments()
894
895
896
897	public function getUsedVarTypes()
898	{
899	return $this->arUsedVarTypes;
900	}//public function getUsedVarTypes()
901
902
903
904	/**
905	* Removes all NULL values from an array and returns it.
906	*
907	* @param array $array Some array
908	* @return array $array without the NULL values.
909	*/
910	protected static function removeNull($array)
911	{
912	foreach ($array as $key => &$value) {
913	if ($value === null) {
914	unset($array[$key]);
915	}
916	}
917	return $array;
918	}//protected static function removeNull($array)
919
920
921
922	/**
923	* Removes a leading AND from the where clause which would render
924	* the sql illegal.
925	*/
926	protected function fixWhere($strWhere)
927	{
928	$strWhere = ltrim($strWhere);
929	if (substr($strWhere, 0, 4) == 'AND ') {
930	$strWhere = substr($strWhere, 4);
931	}
932	return $strWhere;
933	}//protected function fixWhere($strWhere)
934
935
936
937	protected function getSqlVariableName($var)
938	{
939	$strSparqlVar = (string)$var;
940	if (!isset($this->arVarAssignments[$strSparqlVar]['sqlname'])) {
941	if (preg_match('/[a-zA-Z0-9]+/', substr($strSparqlVar, 1))) {
942	$strName = 'v_' . substr($strSparqlVar, 1);
943	} else {
944	$strName = 'va_' . $this->nSqlVariableNameCount++;
945	}
946	$this->arVarAssignments[$strSparqlVar]['sqlname'] = $strName;
947	}
948	return $this->arVarAssignments[$strSparqlVar]['sqlname'];
949	}//protected function getSqlVariableName($var)
950
951
952
953	protected function getSqlVariableNameValue($var)
954	{
955	$strSparqlVar = (string)$var;
956	$this->arVarAssignments[$strSparqlVar]['sql_value'] =
957	'value_' . $this->getSqlVariableName($var);
958	return $this->arVarAssignments[$strSparqlVar]['sql_value'];
959	}//protected function getSqlVariableNameValue($var)
960
961
962
963	protected function getSqlVariableNameIs($var)
964	{
965	$strSparqlVar = (string)$var;
966	$this->arVarAssignments[$strSparqlVar]['sql_is'] =
967	'is_' . $this->getSqlVariableName($var);
968	return $this->arVarAssignments[$strSparqlVar]['sql_is'];
969	}//protected function getSqlVariableNameIs($var)
970
971
972
973	protected function getSqlVariableNameLanguage($var)
974	{
975	$strSparqlVar = (string)$var;
976	$this->arVarAssignments[$strSparqlVar]['sql_lang'] =
977	'lang_' . $this->getSqlVariableName($var);
978	return $this->arVarAssignments[$strSparqlVar]['sql_lang'];
979	}//protected function getSqlVariableNameLanguage($var)
980
981
982
983	protected function getSqlVariableNameDatatype($var)
984	{
985	$strSparqlVar = (string)$var;
986	$this->arVarAssignments[$strSparqlVar]['sql_type'] =
987	'type_' . $this->getSqlVariableName($var);
988	return $this->arVarAssignments[$strSparqlVar]['sql_type'];
989	}//protected function getSqlVariableNameDatatype($var)
990
991
992
993	public function setStatementsTable($tblStatements)
994	{
995	$this->tblStatements = $tblStatements;
996	}//public function setStatementsTable($tblStatements)
997
998	}//class SparqlEngineDb_SqlGenerator
999	?>

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