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os/persistentdata/persistentstorage/dbms/pcdbms/utable/UT_QUERY.CPP
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib. 
     1 // Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 //

    15 

    16 #include "UT_STD.H"

    17 #include "D32COMP.H"

    18 #include "U32STD_DBMS.H"

    19 

    20 // Class RDbAccessPlan::TPlan

    21 

    22 TInt RDbAccessPlan::TPlan::OrderByPlan(const TPlan& aLeft,const TPlan& aRight)

    23 	{

    24 	TUint lpos=aLeft.Type();

    25 	TUint rpos=aRight.Type();

    26 	__ASSERT(lpos!=0 && rpos!=0 ); // should be no table iterators

    27 	return lpos-rpos;

    28 	}

    29 

    30 RDbAccessPlan::TPlan::TType RDbAccessPlan::TPlan::Type() const

    31 //

    32 // flag values: 0=A, 1=C, 2=B, 3=D, 8=E/F, 10=G/H, 16=M/N, 18=S/T,	20=I/J, 21=K/L, 22=O/P, 23=Q/R	

    33 // This determines order of plans

    34 //	

    35 	{

    36 	const TUint KPosition[]={EPlanA,EPlanC,EPlanB,EPlanD,0,0,0,0,EPlanEF,0,EPlanGH,0,0,0,0,0,EPlanMN,

    37 							 0,EPlanST,0,EPlanIJ,EPlanKL,EPlanOP,EPlanQR};

    38 	return TType(KPosition[iFlags&EMask]);

    39 	}

    40 

    41 // Class RDbAccessPlan::TBounds

    42 

    43 RDbAccessPlan::TBounds::TBounds(const TPlan& aPlan)

    44 	: iLowerPred(aPlan.iLower),iUpperPred(aPlan.iUpper),iLower(0),iUpper(0),iInclusion(0)

    45 	{

    46 	SetLowerBounds();

    47 	SetUpperBounds();

    48 	if (aPlan.iIndex->Key()[0].iOrder==TDbKeyCol::EDesc)

    49 		{

    50 		TDbLookupKey* t=iLower;

    51 		iLower=iUpper;

    52 		iUpper=t;

    53 		iInclusion=(iInclusion>>1)|(iInclusion<<1);

    54 		}

    55 	}

    56 

    57 void RDbAccessPlan::TBounds::GetLookupKey(const CSqlCompPredicate& aCompPredicate,TDbLookupKey& aLookup)

    58 	{

    59 	const RSqlLiteral& value=aCompPredicate.Value();

    60 	switch (aCompPredicate.ColType())

    61 		{

    62 	default:

    63 		__ASSERT(0);

    64 	case EDbColBit:

    65 	case EDbColInt8:

    66 	case EDbColUint8:

    67 	case EDbColInt16:

    68 	case EDbColUint16:

    69 	case EDbColInt32:

    70 	case EDbColUint32:

    71 	case EDbColInt64:

    72 		aLookup.Add(value.Int64());

    73 		break;

    74 	case EDbColReal32:

    75 	case EDbColReal64:

    76 		aLookup.Add(value.Real64());

    77 		break;

    78 	case EDbColDateTime:

    79 		aLookup.Add(value.Time());

    80 		break;

    81 	case EDbColText8:

    82 	case EDbColLongText8:

    83 		aLookup.Add(value.Text8());

    84 		break;

    85 	case EDbColText16:

    86 	case EDbColLongText16:

    87 		aLookup.Add(value.Text16());

    88 		break;

    89 		}

    90 	}

    91 

    92 void RDbAccessPlan::TBounds::SetLowerBounds()

    93 	{

    94 	if (!iLowerPred) // iLower already set to 0

    95 		return;

    96 	GetLookupKey(*iLowerPred,iLowerKey);

    97 	switch (iLowerPred->NodeType())

    98 		{

    99 	default:

   100 		__ASSERT(0);

   101 	case CSqlSearchCondition::ELessEqual:

   102 	case CSqlSearchCondition::ELess:

   103 		iLower=0;

   104 		break;

   105 	case CSqlSearchCondition::EEqual:

   106 	case CSqlSearchCondition::EGreaterEqual:

   107 		iInclusion|=CDbRecordIndex::EIncludeLower;

   108 	case CSqlSearchCondition::EGreater:

   109 		iLower=&iLowerKey;

   110 		break;

   111 		}

   112 	}

   113 

   114 void RDbAccessPlan::TBounds::SetUpperBounds()

   115 	{	

   116 	if (!iUpperPred)

   117 		return;

   118 	GetLookupKey(*iUpperPred,iUpperKey);

   119 	switch (iUpperPred->NodeType())

   120 		{

   121 	default:

   122 		__ASSERT(0);

   123 	case CSqlSearchCondition::EGreaterEqual:

   124 	case CSqlSearchCondition::EGreater:

   125 		iUpper=0;

   126 		break;

   127 	case CSqlSearchCondition::EEqual:

   128 	case CSqlSearchCondition::ELessEqual:

   129 		iInclusion|=CDbRecordIndex::EIncludeUpper;

   130 	case CSqlSearchCondition::ELess:

   131 		iUpper=&iUpperKey;

   132 		break;

   133 		}

   134 	}

   135 

   136 // Class RDbAccessPlan::CDbCompPredicateList

   137 

   138 RDbAccessPlan::CDbCompPredicateList* RDbAccessPlan::CDbCompPredicateList::NewLC(CSqlQuery& aQuery,TDbTextComparison aComparison,const CDbTableDef& aTableDef)

   139 	{

   140 	CDbCompPredicateList* self=new(ELeave) CDbCompPredicateList(aTableDef,aComparison);

   141 	CleanupStack::PushL(self);

   142 	CSqlSearchCondition& sc=aQuery.SearchCondition();

   143 	self->ConstructL(sc);

   144 	return self;

   145 	}

   146 

   147 void RDbAccessPlan::CDbCompPredicateList::ConstructL(CSqlSearchCondition& aSearchCondition)

   148 //

   149 // fill the list with valid comp pred's

   150 //

   151 	{

   152 	TUint type=Type(aSearchCondition.NodeType());

   153 	if (type&ECompPred) 

   154 		{

   155 		CSqlCompPredicate* cp=aSearchCondition.CompPredicate();

   156 		const TDesC& colName=cp->ColumnName();

   157 		if (IsIndexed(colName))

   158 			AppendL(cp);

   159 		else

   160 			iRestriction=ETrue;

   161 		}

   162 	else if (type&EAnd)	

   163 		{

   164 		CSqlMultiNode* multiNode=aSearchCondition.MultiNode();	

   165 		for (TInt ii=multiNode->Count();ii--;)				

   166 			{

   167 			CSqlSearchCondition* node=multiNode->SubNode(ii);

   168 			ConstructL(*node);

   169 			}

   170 		}	

   171 	else

   172 		iRestriction=ETrue;

   173 	}

   174 

   175 TUint RDbAccessPlan::CDbCompPredicateList::Type(CSqlSearchCondition::TType aType) const

   176 //

   177 // converts CSqlSearchCondition::TType into flag

   178 //

   179 	{

   180 	switch (aType)

   181 		{

   182 	case CSqlSearchCondition::EAnd:

   183 		return EAnd;

   184 	case CSqlSearchCondition::ELess:

   185 		return ELess;

   186 	case CSqlSearchCondition::ELessEqual:

   187 		return ELessEqual;

   188 	case CSqlSearchCondition::EEqual:

   189 		return EEqual;

   190 	case CSqlSearchCondition::EGreaterEqual:

   191 		return EGreaterEqual;

   192 	case CSqlSearchCondition::EGreater:

   193 		return EGreater;

   194 	default:

   195 		return ENone;

   196 		}

   197 	}

   198 

   199 TBool RDbAccessPlan::CDbCompPredicateList::IsIndexed(const TDesC& aColumnName)

   200 //

   201 // Checks if aColumnName is indexed. If its a text column the comparison method should be the same

   202 //

   203 	{

   204 	const CDbTableIndexDef* key=iTableDef.Key(aColumnName);

   205 	if (!key)

   206 		return EFalse;

   207 	const TDbColumnDef* colDef=NULL;

   208 	TRAPD(errCode, colDef=iTableDef.Columns().ColumnL(aColumnName));

   209 	if(errCode != KErrNone)

   210 		return EFalse;

   211 	if (colDef->Type()>EDbColDateTime && key->Key().Comparison()!=iComparison)

   212 		return EFalse;

   213 	return ETrue;

   214 	}

   215 

   216 CSqlCompPredicate* RDbAccessPlan::CDbCompPredicateList::CompPredicate(TDbColNo aColNo,TUint aType)

   217 //

   218 // Returns first CompPredicate found in the list with required type & col no, and removes from list

   219 //

   220 	{

   221 	for (TInt ii=Count();ii--;)

   222 		{

   223 		CSqlCompPredicate* cp=At(ii);

   224 		TUint type=Type(cp->NodeType());

   225 		TDbColNo colNo=cp->ColNo();

   226 		if (!type&aType || aColNo!=colNo)

   227 			continue;

   228 		Delete(ii);

   229 		return cp;

   230 		}

   231 	return 0;

   232 	}

   233 

   234 // class Validate

   235 

   236 void Validate::NameL(const TDesC& aName)

   237 	{

   238 	if (aName.Length()<=KDbMaxName)

   239 		{

   240 		TLex lex(aName);

   241 		if (!lex.Eos() && lex.Get().IsAlpha())

   242 			{

   243 			TChar c;

   244 			do

   245 				{

   246 				if (lex.Eos())

   247 					return;

   248 				c=lex.Get();

   249 				} while (c.IsAlphaDigit()||c=='_');

   250 			}

   251 		}

   252 	__LEAVE(KErrBadName);

   253 	}

   254 

   255 void Validate::UniqueNameL(TDesC const** aNames,TInt aCount,const TDesC& aName)

   256 //

   257 // Ensure that aName is not a duplicate of any of aNames, and add

   258 // the new name to the collection. Binary search is used for speed

   259 //

   260 	{

   261 	TInt left=0;

   262 	TInt right=aCount;

   263 	while (left<right)

   264 		{

   265 		TInt mid=(left+right)>>1;

   266 		TInt c=aNames[mid]->CompareF(aName);

   267 		if (c<0)

   268 			left=mid+1;

   269 		else if (c>0)

   270 			right=mid;

   271 		else

   272 			__LEAVE(KErrArgument);

   273 		}

   274 	Mem::Move(aNames+left+1,aNames+left,(aCount-left)*sizeof(TDesC const*));

   275 	aNames[left]=&aName;

   276 	}

   277 

   278 void Validate::ColSetL(const CDbColSet& aColSet)

   279 	{

   280 	TDbColSetIter iter(aColSet);

   281 	if (!iter)

   282 		__LEAVE(KErrArgument);

   283 	TDesC const** names=(TDesC const**)User::AllocLC(aColSet.Count()*sizeof(TDesC const*));

   284 	do

   285 		{

   286 		const TDbCol& col=*iter;

   287 		NameL(col.iName);

   288 		UniqueNameL(names,iter.Col()-1,col.iName);

   289 		TInt type=TInt(col.iType);

   290 		if (type<TInt(EDbColBit)||type>TInt(EDbColLongBinary))

   291 			__LEAVE(KErrNotSupported);

   292 		else if (col.iMaxLength<1&&col.iMaxLength!=KDbUndefinedLength)

   293 			__LEAVE(KErrArgument);

   294 		else if (col.iAttributes&~(TDbCol::ENotNull|TDbCol::EAutoIncrement))

   295 			__LEAVE(KErrNotSupported);				// unknown attributes

   296 		else if (type>EDbColUint32 && col.iAttributes&TDbCol::EAutoIncrement)

   297 			__LEAVE(KErrArgument);					// auto increment on non-integral type

   298 		} while (++iter);

   299 	CleanupStack::PopAndDestroy();

   300 	}

   301 

   302 void Validate::KeyL(const CDbKey& aKey,const HDbColumnSet& aColumns)

   303 //

   304 // Check that the key is valid for the table

   305 //

   306 	{

   307 	TInt max=aKey.Count()-1;

   308 	if (max<0)

   309 		__LEAVE(KErrArgument);

   310 	for (TInt ii=0;ii<=max;++ii)

   311 		{

   312 		const TDbKeyCol& kCol=aKey[ii];

   313 		HDbColumnSet::TIteratorC col=aColumns.ColumnL(kCol.iName);

   314 		if (col==NULL)

   315 			__LEAVE(KErrNotFound);

   316 		TInt len=kCol.iLength;

   317 		if (len!=KDbUndefinedLength)

   318 			{

   319 			if (col->iType<=EDbColDateTime)

   320 				__LEAVE(KErrArgument);

   321 			TInt cLen=col->iMaxLength;

   322 			if (ii<max)

   323 				{

   324 				if (len!=cLen)

   325 					__LEAVE(KErrNotSupported);

   326 				continue;

   327 				}

   328 			if (len<=0)

   329 				__LEAVE(KErrArgument);

   330 			else if (cLen!=KDbUndefinedLength && cLen<len)

   331 				__LEAVE(KErrArgument);

   332 			}

   333 		}

   334 	}

   335 

   336 // Class RDbAccessPlan

   337 

   338 TUint RDbAccessPlan::FindMatchL(const CDbTableIndexDef* aIndex)

   339 //

   340 // Checks if index best matches the order specified

   341 //

   342 	{

   343 	CDbKey& order=iQuery->SortSpecification();

   344 	TInt count=order.Count();

   345 	TInt columnLength=iTable->Def().Columns().ColumnL(order[count-1].iName)->iMaxLength;

   346 	const CDbKey& key=aIndex->Key();

   347 	TUint ret=0;

   348 	if (TextKeyL(order) && order.Comparison()!=key.Comparison())

   349 		return ret;

   350 	TInt kCount=key.Count();

   351 	for (TInt ii=0,rev=0;;)

   352 		{

   353 		const TDbKeyCol& kcol=key[ii];

   354 		const TDbKeyCol& ocol=order[ii];

   355 		if (kcol.iName.CompareF(ocol.iName)!=0)

   356 			break;

   357 		TInt revcol=kcol.iOrder^ocol.iOrder;

   358 		if (ii==0)

   359 			rev=revcol;

   360 		else if (rev!=revcol)

   361 			break;

   362 		if (++ii==count)	// end of order key	

   363 			{

   364 			ret|=EMatch;

   365 			if (kcol.iLength!=columnLength)

   366 				ret|=ETruncated;

   367 			if (rev)

   368 				ret|=EReverse;

   369 			return ret;

   370 			}

   371 		if (ii==kCount)		// end of index key

   372 			{

   373 			ret|=EMatch;

   374 			if (key.IsUnique())

   375 				{			// will provide the right order by, use it

   376 				if (rev)

   377 					ret|=EReverse;

   378 			return ret;

   379 				}

   380 			break;

   381 			}

   382 		}

   383 	return ret;

   384 	}

   385 

   386 TBool RDbAccessPlan::TextKeyL(const CDbKey& anOrder)

   387 //

   388 // return whether any of the keys are text columns

   389 //

   390 	{

   391 	const HDbColumnSet& cols=iTable->Def().Columns();

   392 	TInt count=anOrder.Count();

   393 	for (TInt ii=0;ii<count;++ii)

   394 		{

   395 		switch (cols.ColumnL(anOrder[ii].iName)->Type())

   396 			{

   397 		case EDbColText8:

   398 		case EDbColText16:

   399 		case EDbColLongText8:

   400 		case EDbColLongText16:

   401 			return ETrue;

   402 		default:

   403 			break;

   404 			}

   405 		}

   406 	return EFalse;

   407 	}

   408 

   409 CDbTableSource* RDbAccessPlan::TableLC(CDbTableDatabase& aDatabase,const TDesC& aTable)

   410 	{

   411 	__ASSERT(!iSource);

   412 	CDbTableSource* source=aDatabase.TableSourceL(aTable);

   413 	iSource=source;

   414 	iTable=&source->Table();

   415 	CleanupStack::PushL(TCleanupItem(Cleanup,this));

   416 	return source;

   417 	}

   418 

   419 void RDbAccessPlan::Insert(CDbDataStage* aStage)

   420 	{

   421 	__ASSERT(iSource);

   422 	aStage->SetSource(iSource);

   423 	iSource=aStage;

   424 	}

   425 

   426 void RDbAccessPlan::Cleanup(TAny* aPtr)

   427 	{

   428 	RDbAccessPlan& self=*STATIC_CAST(RDbAccessPlan*,aPtr);

   429 	self.iPlans.Close();

   430 	delete self.iSource;

   431 	}

   432 

   433 CDbRecordIter* RDbAccessPlan::IteratorL(const TPlan& aPlan)

   434 //

   435 // Returns the right iterator

   436 //

   437 	{

   438 	if (aPlan.iFlags&TPlan::EIndex)

   439 		return iTable->IteratorL(*aPlan.iIndex);

   440 	if (aPlan.iFlags&TPlan::EBounded)

   441 		return BoundedIteratorL(aPlan);

   442 	return iTable->IteratorL();

   443 	}

   444 

   445 CDbRecordIter* RDbAccessPlan::BoundedIteratorL(const TPlan& aPlan)

   446 	{

   447 	TBounds bounds(aPlan);

   448 	CDbRecordIter* iter=iTable->IteratorL(*aPlan.iIndex,bounds.iInclusion,bounds.iLower,bounds.iUpper);

   449 	if (aPlan.iLower)

   450 		iQuery->RemovePredicate(aPlan.iLower);

   451 	if (aPlan.iUpper && aPlan.iLower!=aPlan.iUpper)

   452 		iQuery->RemovePredicate(aPlan.iUpper);

   453 	return iter;

   454 	}

   455 

   456 void RDbAccessPlan::RestrictionL()

   457 	{

   458 	CDbRestrictStage* restriction=new(ELeave) CDbRestrictStage(iComparison);

   459 	Insert(restriction);

   460 	CSqlSearchCondition* searchcondition=iQuery->AdoptSearchCondition();

   461 	restriction->SetRestriction(searchcondition);

   462 	}

   463 

   464 void RDbAccessPlan::OrderByL(const RDbTableRow& aRowBuf)

   465 	{

   466 	CDbOrderByStage* ordering=new(ELeave) CDbOrderByStage(aRowBuf);

   467 	Insert(ordering);

   468 	ordering->ConstructL(iQuery->SortSpecification());

   469 	}

   470 

   471 void RDbAccessPlan::ProjectionL()

   472 	{

   473 	CDbProjectStage* projection=new(ELeave) CDbProjectStage;

   474 	Insert(projection);

   475 	projection->ConstructL(iQuery->ColumnList(),iTable->Def().Columns());

   476 	}

   477 

   478 void RDbAccessPlan::WindowL(const TPlan& aPlan,const TDbWindow& aWindow)

   479 	{

   480 	if (aPlan.iFlags&TPlan::EWindow)

   481 		Insert(new(ELeave) CDbWindowStage(KDbUnlimitedWindow));

   482 	else if (aWindow.Size()!=aWindow.ENone && aWindow.Size()!=aWindow.EUnlimited)

   483 		Insert(new(ELeave) CDbWindowStage(aWindow));

   484 	}

   485 

   486 TBool RDbAccessPlan::IsIndexIteratorL(TPlan& aPlan,const CDbTableIndexDef* aIndex)

   487 //

   488 // If an index iterator can be used, sets aPlan, else returns EFalse

   489 //

   490 	{

   491 	if (!iQuery->HasSortSpecification())

   492 		return EFalse;

   493 	TUint ret=FindMatchL(aIndex);

   494 	if ((ret&EMatch)==0)

   495 		return EFalse;

   496 	// can use index iterator

   497 	aPlan.iFlags&=~TPlan::EOrder;

   498 	if (ret&EReverse)

   499 		aPlan.iFlags|=TPlan::EReverse;

   500 	aPlan.iFlags|=TPlan::EIndex;

   501 	aPlan.iIndex=aIndex;

   502 	return ETrue;

   503 	}

   504 

   505 TBool RDbAccessPlan::IsBoundedIteratorL(TPlan& aPlan,const CDbTableIndexDef* aIndex)

   506 //

   507 // If a bounded iterator can be used, sets aPlan, else returns EFalse

   508 //

   509 	{

   510 	if (!iQuery->HasSearchCondition())

   511 		return EFalse;

   512 	TDbColNo keyColNo=iTable->Def().Columns().ColNoL(aIndex->Key()[0].iName);

   513 	CDbCompPredicateList* list=CDbCompPredicateList::NewLC(*iQuery,iComparison,iTable->Def());

   514 	CSqlCompPredicate* cp=list->CompPredicate(keyColNo,CDbCompPredicateList::EEqual); 

   515 	if (cp==0 && (cp=list->CompPredicate(keyColNo))==0)								   

   516 		{

   517 		CleanupStack::PopAndDestroy(); // list

   518 		return EFalse; 

   519 		}

   520 	// boundaries

   521 	TUint type=list->Type(cp->NodeType());

   522 	aPlan.iLower=type&(CDbCompPredicateList::ELess|CDbCompPredicateList::ELessEqual)?0:cp;

   523 	aPlan.iUpper=type&(CDbCompPredicateList::EGreater|CDbCompPredicateList::EGreaterEqual)?0:cp;

   524 	// find other boundary, if present

   525 	if (list->Count()!=0 && cp->NodeType()!=CSqlSearchCondition::EEqual)	

   526 		{

   527 		TUint nextType=type&(CDbCompPredicateList::ELess|CDbCompPredicateList::ELessEqual) ? 

   528 			CDbCompPredicateList::EGreater|CDbCompPredicateList::EGreaterEqual : 

   529 			CDbCompPredicateList::ELess|CDbCompPredicateList::ELessEqual;

   530 		CSqlCompPredicate* cp2=list->CompPredicate(keyColNo,nextType);

   531 		if (cp2)

   532 			{

   533 			if (nextType&(CDbCompPredicateList::ELess|CDbCompPredicateList::ELessEqual))

   534 				aPlan.iUpper=cp2;

   535 			else

   536 				aPlan.iLower=cp2;

   537 			}

   538 		}	

   539 	// check which order the index is in and reverse if descending

   540 	const TDbKeyCol& key=aIndex->Key()[0];

   541 	if ((key.iOrder==TDbKeyCol::EDesc && !aPlan.iUpper) || (key.iOrder==TDbKeyCol::EAsc && !aPlan.iLower))

   542 		aPlan.iFlags|=TPlan::EReverse;				// optimise the bounding for forwards iteration

   543 	if (!list->IsRestriction() && list->Count()==0)

   544 		aPlan.iFlags&=~TPlan::ERestrict;

   545 	CleanupStack::PopAndDestroy();			// list

   546 	aPlan.iFlags|=TPlan::EBounded;

   547 	aPlan.iIndex=aIndex;

   548 	return ETrue;

   549 	}

   550 

   551 void RDbAccessPlan::EvaluatePlansL()

   552 //

   553 // try to find a bounded or index iterator

   554 //

   555 	{

   556 	TPlan plan;

   557 	// initialise flags

   558 	if (iQuery->HasSearchCondition())

   559 		plan.iFlags|=TPlan::ERestrict;

   560 	if (iQuery->HasSortSpecification())

   561 		plan.iFlags|=TPlan::EOrder;

   562 	// find the right type of iterator

   563 	TSglQueIterC<CDbTableIndexDef> indexes(iTable->Def().Indexes().AsQue());

   564 	for (const CDbTableIndexDef* index;(index=indexes++)!=0;)

   565 		{ // only on first column

   566 		TPlan newPlan=plan;

   567 		TBool foundIter=IsBoundedIteratorL(newPlan,index);

   568 		if (!foundIter)

   569 			foundIter=IsIndexIteratorL(newPlan,index);

   570 		else

   571 			EvaluateReorderStage(newPlan,index);

   572 		if (foundIter)

   573 			{

   574 			EvaluateWindowStage(newPlan);

   575 			__LEAVE_IF_ERROR(iPlans.Append(newPlan));

   576 			}

   577 		}

   578 	}

   579 

   580 void RDbAccessPlan::ChoosePlanL(TPlan& aPlan)

   581 	{

   582 	ReducePlans();

   583 	if (iPlans.Count()==0)

   584 		{

   585 		CreateTableIteratorPlan(aPlan);

   586 		return;

   587 		}

   588 	TPlan::TType type=iPlans[0].Type();

   589 	if (!iQuery->HasSearchCondition())						

   590 		{													

   591 		__ASSERT(type==TPlan::EPlanEF);

   592 		GetSmallestKeySize(aPlan,TPlan::EPlanEF);

   593 		}

   594 	else if (!iQuery->HasSortSpecification())					

   595 		{													

   596 		if (type==TPlan::EPlanIJ)								

   597 			{	

   598 			GetSmallestKeySize(aPlan,TPlan::EPlanIJ);

   599 			TInt r=IndexSpanL(aPlan);

   600 			if (r!=CDbTable::EUnavailableSpan && !iWindow && r>60)

   601 				CreateTableIteratorPlan(aPlan);

   602 			}

   603 		else if (type==TPlan::EPlanOP)					

   604 			{

   605 			TInt r=GetTightestRestrictionL(aPlan,TPlan::EPlanOP);

   606 			if (r==CDbTable::EUnavailableSpan)	// no index stats available

   607 				aPlan=iPlans[0];				// use first O/P as a guess

   608 			else if ((!iWindow && r>55) || (iWindow && r>60))

   609 				CreateTableIteratorPlan(aPlan);

   610 			}

   611 		else

   612 			__ASSERT(0);

   613 		}

   614 	else if (type==TPlan::EPlanMN) 

   615 		{

   616 		GetSmallestKeySize(aPlan,TPlan::EPlanMN);

   617 		if (iAccess==RDbRowSet::EUpdatable || iWindow)

   618 			aPlan.iFlags|=TPlan::EWindow;

   619 		}

   620 	else if (type==TPlan::EPlanKL) 

   621 		{	

   622 		GetSmallestKeySize(aPlan,TPlan::EPlanKL);

   623 		TInt r=IndexSpanL(aPlan);

   624 		if (r!=CDbTable::EUnavailableSpan && r>60)

   625 			{	// don't use K plan

   626 			if (r<75 || GetSmallestKeySize(aPlan,TPlan::EPlanGH)==KErrNotFound)

   627 				CreateTableIteratorPlan(aPlan);	

   628 			}

   629 		}

   630 	else if (type==TPlan::EPlanQR) 

   631 		{

   632 		TInt r=GetTightestRestrictionL(aPlan,TPlan::EPlanQR);

   633 		if (r==CDbTable::EUnavailableSpan)			// no index stats available

   634 			aPlan=iPlans[0];						// use first Q/R as a guess

   635 		else if (r>60)

   636 			CreateTableIteratorPlan(aPlan);	

   637 		}

   638 	else 

   639 		{

   640 		__ASSERT(type==TPlan::EPlanGH);

   641 		// don't use this plan without further data, resort to default

   642 		CreateTableIteratorPlan(aPlan);	

   643 		}

   644 	}

   645 

   646 void RDbAccessPlan::EvaluateWindowStage(TPlan& aPlan)

   647 	{

   648 	if (!iWindow)

   649 		return;

   650 	TUint f=aPlan.iFlags|TPlan::EWindow;

   651 	if (f&TPlan::EReorder)

   652 		f&=~TPlan::EWindow;

   653 	if (f&TPlan::ERestrict)

   654 		f|=TPlan::EWindow; 

   655 	if (f&TPlan::EOrder)						// order-by stage includes window

   656 		f&=~TPlan::EWindow;

   657 	aPlan.iFlags=f;

   658 	}

   659 

   660 TInt RDbAccessPlan::GetTightestRestrictionL(TPlan& aPlan,TPlan::TType aType)

   661 //

   662 // aPlan is set to the smallest restricted plan with aType

   663 //

   664 	{

   665 	TInt span=KMaxTInt;

   666 	TPlan plan;

   667 	for (TInt ii=iPlans.Count();ii--;)

   668 		{

   669 		if (iPlans[ii].Type()!=aType)

   670 			continue;

   671 		TInt t=IndexSpanL(iPlans[ii]);

   672 		if (t==CDbTable::EUnavailableSpan)

   673 			continue;

   674 		if (t<span || (t==span && iPlans[ii].iIndex->Key().Count()<plan.iIndex->Key().Count()))

   675 			{

   676 			span=t;

   677 			plan=iPlans[ii];

   678 			}

   679 		}

   680 	aPlan=plan;

   681 	return span!=KMaxTInt?span:CDbTable::EUnavailableSpan;

   682 	}

   683 

   684 TInt RDbAccessPlan::GetSmallestKeySize(TPlan& aPlan,TPlan::TType aType)

   685 //

   686 // aPlan is set to the plan with smallest index with aType

   687 //

   688 	{

   689 	TInt cols=KMaxTInt;

   690 	TPlan plan;

   691 	for (TInt ii=iPlans.Count();ii--;)

   692 		{

   693 		if (iPlans[ii].Type()!=aType)

   694 			continue;

   695 		__ASSERT(iPlans[ii].iIndex);

   696 		TInt count=iPlans[ii].iIndex->Key().Count();

   697 		if (count<cols)

   698 			{

   699 			cols=count;

   700 			plan=iPlans[ii];

   701 			}

   702 		}

   703 	aPlan=plan;

   704 	return cols!=KMaxTInt?cols:KErrNotFound;

   705 	}

   706 

   707 TInt RDbAccessPlan::IndexSpanL(const TPlan& aPlan)

   708 	{

   709 	__ASSERT(aPlan.iIndex);

   710 	TBounds bounds(aPlan);

   711 	return iTable->IndexSpanL(*aPlan.iIndex,bounds.iInclusion,bounds.iLower,bounds.iUpper);

   712 	}

   713 

   714 void RDbAccessPlan::ReducePlans()

   715 	{

   716 	for (TInt ii=iPlans.Count();--ii>=0;)

   717 		{

   718 		switch (iPlans[ii].Type())

   719 			{

   720 		default:

   721 			continue;

   722 		case TPlan::EPlanGH:									

   723 			if (iWindow)

   724 				iPlans.Remove(ii);								// remove Gw/Hw 

   725 			break;

   726 		case TPlan::EPlanST:

   727 			iPlans[ii].iFlags|=(TPlan::EReorder|TPlan::EOrder);	// convert S/T to Q/R

   728 			EvaluateWindowStage(iPlans[ii]);

   729 			break;

   730 			};

   731 		}

   732 // explicit conversion required as GCC can't find the TLinearOrder instantiation

   733 	iPlans.Sort(TLinearOrder<TPlan>(TPlan::OrderByPlan));

   734 	}

   735 

   736 void RDbAccessPlan::CreateTableIteratorPlan(TPlan& aPlan)

   737 	{

   738 	aPlan.iFlags&=~(TPlan::EIndex|TPlan::EBounded);

   739 	if (iQuery->HasSearchCondition())

   740 		aPlan.iFlags=TPlan::ERestrict;

   741 	if (iQuery->HasSortSpecification())

   742 		aPlan.iFlags|=TPlan::EOrder;

   743 	EvaluateWindowStage(aPlan);

   744 	}

   745 

   746 void RDbAccessPlan::EvaluateReorderStage(TPlan& aPlan,const CDbTableIndexDef* aIndex)

   747 //

   748 // for a bounded iter with an order by - can the index be used?

   749 //

   750 	{

   751 	aPlan.iFlags|=TPlan::EReorder;

   752 	if (!iQuery->HasSortSpecification())

   753 		return;

   754 	TUint ret=0;

   755 	TRAPD(errCode, ret=FindMatchL(aIndex));

   756 	if (errCode==KErrNone && ret&EMatch)

   757 		{// do we really need a reorder stage?

   758 		aPlan.iFlags&=~TPlan::EOrder;			// don't need to order it

   759 		aPlan.iFlags&=~TPlan::EReorder;			// don't need a reorder stage 

   760 		if (ret&EReverse)			

   761 			aPlan.iFlags|=TPlan::EReverse;

   762 		else

   763 			aPlan.iFlags&=~TPlan::EReverse;

   764 		}

   765 	}

   766 

   767 void RDbAccessPlan::PrepareQueryL(CDbTableSource* aSource)

   768 	{

   769 	if (iQuery->HasSearchCondition())

   770 		{ 

   771 		CSqlSearchCondition& sc=iQuery->SearchCondition();

   772 		sc.BindL(aSource->Row());

   773 		}

   774 	if (iQuery->HasSortSpecification())

   775 		{

   776 		CDbKey& order=iQuery->SortSpecification();

   777 		order.SetComparison(iComparison);

   778 		Validate::KeyL(order,iTable->Def().Columns());

   779 		}

   780 	}

   781 	

   782 

   783 void RDbAccessPlan::BuildLC(CDbTableDatabase& aDatabase,RDbRowSet::TAccess aAccess,const TDbWindow& aWindow)

   784 //

   785 // Prepare the data pipeline

   786 //

   787 	{

   788 	__ASSERT(iQuery);

   789 	CDbTableSource* source=TableLC(aDatabase,iQuery->Table());

   790 	//

   791 	if (aAccess!=RDbRowSet::EInsertOnly)

   792 		{	// insert only views do not use Iterators, Restrictions or Windows

   793 		iWindow=aWindow.Size()==aWindow.EUnlimited;

   794 		iAccess=aAccess;

   795 		PrepareQueryL(source);

   796 		EvaluatePlansL();

   797 		TPlan plan;

   798 		ChoosePlanL(plan);

   799 		source->SetIterator(IteratorL(plan));

   800 		if (plan.iFlags&TPlan::EReorder)

   801 			Insert(new(ELeave) CDbReorderWindowStage); 

   802 		if (plan.iFlags&TPlan::EReverse)

   803 			source->ReverseIteratorL();

   804 		if (plan.iFlags&TPlan::ERestrict)

   805 			RestrictionL();

   806 		if (plan.iFlags&TPlan::EOrder)	

   807 			OrderByL(source->Row());

   808 		WindowL(plan,aWindow);

   809 		iPlans.Reset();

   810 		}

   811 	if (iQuery->HasColumnList())

   812 		ProjectionL();

   813 	}

   814 

   815 void RDbAccessPlan::BuildLC(CDbTableDatabase& aDatabase,const TDesC& aTable,RDbRowSet::TAccess aAccess)

   816 	{

   817 	CDbTableSource* source=TableLC(aDatabase,aTable);

   818 	if (aAccess!=RDbRowSet::EInsertOnly)

   819 		source->SetIterator(iTable->IteratorL());

   820 	}
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