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Add relation discovery for SpatiaLite
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Patrick Valsecchi committed Sep 29, 2016
1 parent 31a1c23 commit ecba25430331bd64307d286752538ecf23701b25
@@ -31,6 +31,7 @@ email : a.furieri@lqt.it
#include "qgsspatialitefeatureiterator.h"

#include <qgsjsonutils.h>
#include <qgsvectorlayer.h>

#include <QMessageBox>
#include <QFileInfo>
@@ -5264,6 +5265,80 @@ QgsAttributeList QgsSpatiaLiteProvider::pkAttributeIndexes() const
return mPrimaryKeyAttrs;
}

QList<QgsVectorLayer*> QgsSpatiaLiteProvider::searchLayers( const QList<QgsVectorLayer*>& layers, const QString& connectionInfo, const QString& tableName )
{
QList<QgsVectorLayer*> result;
Q_FOREACH ( QgsVectorLayer* layer, layers )
{
const QgsSpatiaLiteProvider* slProvider = qobject_cast<QgsSpatiaLiteProvider*>( layer->dataProvider() );
if ( slProvider && slProvider->mSqlitePath == connectionInfo && slProvider->mTableName == tableName )
{
result.append( layer );
}
}
return result;
}


QList<QgsRelation> QgsSpatiaLiteProvider::discoverRelations( const QgsVectorLayer* self, const QList<QgsVectorLayer*>& layers ) const
{
QList<QgsRelation> output;
const QString sql = QString( "PRAGMA foreign_key_list(%1)" ).arg( QgsSpatiaLiteProvider::quotedIdentifier( mTableName ) );
char **results;
int rows;
int columns;
char *errMsg = nullptr;
int ret = sqlite3_get_table( mSqliteHandle, sql.toUtf8().constData(), &results, &rows, &columns, &errMsg );
if ( ret == SQLITE_OK )
{
int nbFound = 0;
for ( int row = 1; row <= rows; ++row )
{
const QString name = "fk_" + mTableName + "_" + QString::fromUtf8( results[row * columns + 0] );
const QString position = QString::fromUtf8( results[row * columns + 1] );
const QString refTable = QString::fromUtf8( results[row * columns + 2] );
const QString fkColumn = QString::fromUtf8( results[row * columns + 3] );
const QString refColumn = QString::fromUtf8( results[row * columns + 4] );
if ( position == "0" )
{ // first reference field => try to find if we have layers for the referenced table
const QList<QgsVectorLayer*> foundLayers = searchLayers( layers, mSqlitePath, refTable );
Q_FOREACH ( const QgsVectorLayer* foundLayer, foundLayers )
{
QgsRelation relation;
relation.setRelationName( name );
relation.setReferencingLayer( self->id() );
relation.setReferencedLayer( foundLayer->id() );
relation.addFieldPair( fkColumn, refColumn );
relation.generateId();
if ( relation.isValid() )
{
output.append( relation );
++nbFound;
}
else
{
QgsLogger::warning( "Invalid relation for " + name );
}
}
}
else
{ // multi reference field => add the field pair to all the referenced layers found
for ( int i = 0; i < nbFound; ++i )
{
output[output.size() - 1 - i].addFieldPair( fkColumn, refColumn );
}
}
}
sqlite3_free_table( results );
}
else
{
QgsLogger::warning( QString( "SQLite error discovering relations: %1" ).arg( errMsg ) );
sqlite3_free( errMsg );
}
return output;
}

// ---------------------------------------------------------------------------

QGISEXTERN bool saveStyle( const QString& uri, const QString& qmlStyle, const QString& sldStyle,
@@ -209,6 +209,8 @@ class QgsSpatiaLiteProvider: public QgsVectorDataProvider

void invalidateConnections( const QString& connection ) override;

QList<QgsRelation> discoverRelations( const QgsVectorLayer* self, const QList<QgsVectorLayer*>& layers ) const override;

// static functions
static void convertToGeosWKB( const unsigned char *blob, int blob_size,
unsigned char **wkb, int *geom_size );
@@ -291,6 +293,11 @@ class QgsSpatiaLiteProvider: public QgsVectorDataProvider
//! get SpatiaLite version string
QString spatialiteVersion();

/**
* Search all the layers using the given table.
*/
static QList<QgsVectorLayer*> searchLayers( const QList<QgsVectorLayer*>& layers, const QString& connectionInfo, const QString& tableName );

QgsFields mAttributeFields;

//! Flag indicating if the layer data source is a valid SpatiaLite layer
@@ -19,7 +19,7 @@
import shutil
import tempfile

from qgis.core import QgsVectorLayer, QgsPoint, QgsFeature, QgsGeometry
from qgis.core import QgsVectorLayer, QgsPoint, QgsFeature, QgsGeometry, QgsProject, QgsMapLayerRegistry

from qgis.testing import start_app, unittest
from utilities import unitTestDataPath
@@ -123,6 +123,18 @@ def setUpClass(cls):
sql += "VALUES (1, '[\"toto\",\"tutu\"]', '[1,-2,724562]', '[1.0, -232567.22]', GeomFromText('POLYGON((0 0,1 0,1 1,0 1,0 0))', 4326))"
cur.execute(sql)

# 2 tables with relations
sql = "PRAGMA foreign_keys = ON;"
cur.execute(sql)
sql = "CREATE TABLE test_relation_a(artistid INTEGER PRIMARY KEY, artistname TEXT);"
cur.execute(sql)
sql = "SELECT AddGeometryColumn('test_relation_a', 'Geometry', 4326, 'POLYGON', 'XY')"
cur.execute(sql)
sql = "CREATE TABLE test_relation_b(trackid INTEGER, trackname TEXT, trackartist INTEGER, FOREIGN KEY(trackartist) REFERENCES test_relation_a(artistid));"
cur.execute(sql)
sql = "SELECT AddGeometryColumn('test_relation_b', 'Geometry', 4326, 'POLYGON', 'XY')"
cur.execute(sql)

cur.execute("COMMIT")
con.close()

@@ -347,6 +359,29 @@ def test_arrays(self):
self.assertEqual(read_back['ints'], new_f['ints'])
self.assertEqual(read_back['reals'], new_f['reals'])

def test_discover_relation(self):
artist = QgsVectorLayer("dbname=%s table=test_relation_a (geometry)" % self.dbname, "test_relation_a", "spatialite")
self.assertTrue(artist.isValid())
track = QgsVectorLayer("dbname=%s table=test_relation_b (geometry)" % self.dbname, "test_relation_b", "spatialite")
self.assertTrue(track.isValid())
QgsMapLayerRegistry.instance().addMapLayer(artist)
QgsMapLayerRegistry.instance().addMapLayer(track)
try:
relMgr = QgsProject.instance().relationManager()
relations = relMgr.discoverRelations([], [artist, track])
relations = {r.name(): r for r in relations}
self.assertEqual({'fk_test_relation_b_0'}, set(relations.keys()))

a2t = relations['fk_test_relation_b_0']
self.assertTrue(a2t.isValid())
self.assertEqual('test_relation_b', a2t.referencingLayer().name())
self.assertEqual('test_relation_a', a2t.referencedLayer().name())
self.assertEqual([2], a2t.referencingFields())
self.assertEqual([0], a2t.referencedFields())
finally:
QgsMapLayerRegistry.instance().removeMapLayer(track.id())
QgsMapLayerRegistry.instance().removeMapLayer(artist.id())

# This test would fail. It would require turning on WAL
def XXXXXtestLocking(self):

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