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Rework QgsHanaFeatureIterator::buildSqlQuery
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@mrylov
Maksim Rylov authored and mrylov committed Dec 7, 2020
1 parent 5364c89 commit 2d8f9b5
Showing 1 changed file with 54 additions and 79 deletions.
133 changes: 54 additions & 79 deletions src/providers/hana/qgshanafeatureiterator.cpp
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Expand Up @@ -27,16 +27,6 @@
#include "qgsmessagelog.h"
#include "qgssettings.h"

static QString andWhereClauses( const QString &c1, const QString &c2 )
{
if ( c1.isEmpty() )
return c2;
if ( c2.isEmpty() )
return c1;

return QStringLiteral( "(%1) AND (%2)" ).arg( c1, c2 );
}

QgsHanaFeatureIterator::QgsHanaFeatureIterator(
QgsHanaFeatureSource *source,
bool ownSource,
Expand Down Expand Up @@ -82,8 +72,7 @@ QgsHanaFeatureIterator::QgsHanaFeatureIterator(

QgsHanaFeatureIterator::~QgsHanaFeatureIterator()
{
if ( !mClosed )
close();
close();
}

bool QgsHanaFeatureIterator::rewind()
Expand All @@ -109,7 +98,12 @@ bool QgsHanaFeatureIterator::close()
if ( mClosed )
return false;

mResultSet->close();
if ( mResultSet )
{
mResultSet->close();
mResultSet.reset();
}

iteratorClosed();
mClosed = true;

Expand Down Expand Up @@ -201,7 +195,9 @@ bool QgsHanaFeatureIterator::prepareOrderBy( const QList<QgsFeatureRequest::Orde

QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request )
{
bool limitAtProvider = ( mRequest.limit() >= 0 );
const bool geometryRequested = ( request.flags() & QgsFeatureRequest::NoGeometry ) == 0;
bool limitAtProvider = ( request.limit() >= 0 );

QgsRectangle filterRect = mFilterRect;
if ( !mSrsExtent.isEmpty() )
filterRect = mSrsExtent.intersect( filterRect );
Expand Down Expand Up @@ -249,84 +245,60 @@ QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request
limitAtProvider = false;

bool subsetOfAttributes = mRequest.flags() & QgsFeatureRequest::SubsetOfAttributes;
QgsAttributeList attrs = ( subsetOfAttributes ) ?
request.subsetOfAttributes() : mSource->mFields.allAttributesList();
QgsAttributeIds attrIds = subsetOfAttributes ?
request.subsetOfAttributes().toSet() : mSource->mFields.allAttributesList().toSet();

if ( subsetOfAttributes )
{
// Ensure that all attributes required for expression filter are fetched
if ( mRequest.filterType() == QgsFeatureRequest::FilterExpression )
auto addAttributeIds = [&attrIds]( const QSet<int> &ids )
{
//ensure that all fields required for filter expressions are prepared
QSet<int> attributeIndexes = request.filterExpression()->referencedAttributeIndexes( mSource->mFields );
attributeIndexes += attrs.toSet();
attrs = attributeIndexes.toList();
}
for ( int id : ids )
if ( !attrIds.contains( id ) )
attrIds << id;
};

if ( mRequest.filterType() == QgsFeatureRequest::FilterExpression )
// Ensure that all attributes required for expression filter are fetched
addAttributeIds( request.filterExpression()->referencedAttributeIndexes( mSource->mFields ) );

if ( !mRequest.orderBy().isEmpty() )
{
// Ensure that all attributes required for order by are fetched
const auto usedAttributeIndices = mRequest.orderBy().usedAttributeIndices( mSource->mFields );
for ( int attrIndex : usedAttributeIndices )
{
if ( !attrs.contains( attrIndex ) )
attrs << attrIndex;
}
}
addAttributeIds( mRequest.orderBy().usedAttributeIndices( mSource->mFields ) );
}

for ( int i : attrs )
{
QString fieldname = mSource->mFields.at( i ).name();
if ( mFidColumn == fieldname )
continue;
mAttributesToFetch.append( i );
}

QString sqlFields = "";

QStringList sqlFields;
// Add feature id column
if ( !mFidColumn.isEmpty() )
sqlFields += QgsHanaUtils::quotedIdentifier( mFidColumn ) + ",";
sqlFields.push_back( QgsHanaUtils::quotedIdentifier( mFidColumn ) );

for ( int i : mAttributesToFetch )
for ( int i : attrIds )
{
QString fieldname = mSource->mFields.at( i ).name();
sqlFields += QStringLiteral( "%1," ).arg( QgsHanaUtils::quotedIdentifier( fieldname ) );
QString fieldName = mSource->mFields.at( i ).name();
if ( mFidColumn != fieldName )
{
mAttributesToFetch.append( i );
sqlFields.push_back( QgsHanaUtils::quotedIdentifier( fieldName ) );
}
}

mHasAttributes = !mAttributesToFetch.isEmpty();

// Add geometry column
if ( ( !( request.flags() & QgsFeatureRequest::NoGeometry )
|| ( request.filterType() == QgsFeatureRequest::FilterExpression &&
request.filterExpression()->needsGeometry() ) ) && mSource->isSpatial() )
if ( mSource->isSpatial() &&
( geometryRequested || ( request.filterType() == QgsFeatureRequest::FilterExpression &&
request.filterExpression()->needsGeometry() ) ) )
{
sqlFields += QStringLiteral( "%1" ).arg( QgsHanaUtils::quotedIdentifier( mSource->mGeometryColumn ) );
sqlFields += QgsHanaUtils::quotedIdentifier( mSource->mGeometryColumn );
mHasGeometryColumn = true;
}

if ( sqlFields.isEmpty() )
{
sqlFields = "*";
}
else
{
if ( sqlFields.endsWith( ',' ) )
sqlFields.truncate( sqlFields.length() - 1 );
}

QString sql = QStringLiteral( "SELECT %1 FROM %2.%3" ).arg(
sqlFields,
QgsHanaUtils::quotedIdentifier( mSource->mSchemaName ),
QgsHanaUtils::quotedIdentifier( mSource->mTableName ) );

QString sqlFilter;
QStringList sqlFilter;
// Set spatial filter
if ( !( filterRect.isNull() || filterRect.isEmpty() ) && mSource->isSpatial() && mHasGeometryColumn )
sqlFilter = getBBOXFilter( QgsHanaUtils::toHANAVersion( mConnection->getDatabaseVersion() ) );
if ( mSource->isSpatial() && mHasGeometryColumn && !( filterRect.isNull() || filterRect.isEmpty() ) )
sqlFilter.push_back( getBBOXFilter( QgsHanaUtils::toHANAVersion( mConnection->getDatabaseVersion() ) ) );

if ( !mSource->mQueryWhereClause.isEmpty() )
sqlFilter = andWhereClauses( sqlFilter, mSource->mQueryWhereClause );
sqlFilter.push_back( mSource->mQueryWhereClause );

// Set fid filter
if ( !mFidColumn.isEmpty() )
Expand All @@ -335,20 +307,17 @@ QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request
{
QString inClause = QStringLiteral( " %1 = %2" ).arg(
QgsHanaUtils::quotedIdentifier( mFidColumn ), FID_TO_STRING( request.filterFid() ) );
sqlFilter = andWhereClauses( sqlFilter, inClause );
sqlFilter.push_back( inClause );
}
else if ( request.filterType() == QgsFeatureRequest::FilterFids && !mRequest.filterFids().isEmpty() )
{
QString delim;
QString inClause = QStringLiteral( "%1 IN (" ).arg( QgsHanaUtils::quotedIdentifier( mFidColumn ) );
QStringList fids;
for ( QgsFeatureId featureId : mRequest.filterFids() )
{
inClause += delim + FID_TO_STRING( featureId );
delim = ',';
}
inClause.append( ')' );
fids.push_back( FID_TO_STRING( featureId ) );

sqlFilter = andWhereClauses( sqlFilter, inClause );
QString inClause = QStringLiteral( "%1 IN (" ).arg( QgsHanaUtils::quotedIdentifier( mFidColumn ) ) +
fids.join( QStringLiteral( "," ) ) + QStringLiteral( ")" );
sqlFilter.push_back( inClause );
}
}

Expand All @@ -369,7 +338,7 @@ QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request
QString filterExpr = compiler.result();
if ( !filterExpr.isEmpty() )
{
sqlFilter = andWhereClauses( sqlFilter, filterExpr );
sqlFilter.push_back( filterExpr );
//if only partial success when compiling expression, we need to double-check results
//using QGIS' expressions
mExpressionCompiled = ( result == QgsSqlExpressionCompiler::Result::Complete );
Expand All @@ -396,8 +365,13 @@ QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request
}
}

QString sql = QStringLiteral( "SELECT %1 FROM %2.%3" ).arg(
sqlFields.isEmpty() ? QStringLiteral( "*" ) : sqlFields.join( QStringLiteral( "," ) ),
QgsHanaUtils::quotedIdentifier( mSource->mSchemaName ),
QgsHanaUtils::quotedIdentifier( mSource->mTableName ) );

if ( !sqlFilter.isEmpty() )
sql += QStringLiteral( " WHERE " ) + sqlFilter;
sql += QStringLiteral( " WHERE (" ) + sqlFilter.join( ") AND (" ) + QStringLiteral( ")" );

if ( !orderByParts.isEmpty() )
sql += QStringLiteral( " ORDER BY %1 " ).arg( orderByParts.join( QStringLiteral( "," ) ) );
Expand All @@ -406,6 +380,7 @@ QString QgsHanaFeatureIterator::buildSqlQuery( const QgsFeatureRequest &request
sql += QStringLiteral( " LIMIT %1" ).arg( mRequest.limit() );

QgsDebugMsgLevel( "Query: " + sql, 4 );

return sql;
}

Expand Down

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