Allow to open a spatialite table without primary key

Author: Hugo Mercier

src/providers/spatialite/qgsspatialitefeatureiterator.cpp

@@ -31,6 +31,8 @@ QgsSpatiaLiteFeatureIterator::QgsSpatiaLiteFeatureIterator( QgsSpatiaLiteFeature
   mHandle = QgsSpatiaLiteConnPool::instance()->acquireConnection( mSource->mSqlitePath );
 
   mFetchGeometry = !mSource->mGeometryColumn.isNull() && !( mRequest.flags() & QgsFeatureRequest::NoGeometry );
+  mHasPrimaryKey = !mSource->mPrimaryKey.isEmpty();
+  mRowNumber = 0;
 
   QString whereClause;
   if ( request.filterType() == QgsFeatureRequest::FilterRect && !mSource->mGeometryColumn.isNull() )
@@ -108,6 +110,7 @@ bool QgsSpatiaLiteFeatureIterator::rewind()
 
   if ( sqlite3_reset( sqliteStatement ) == SQLITE_OK )
   {
+    mRowNumber = 0;
     return true;
   }
   else
@@ -143,7 +146,7 @@ bool QgsSpatiaLiteFeatureIterator::prepareStatement( QString whereClause )
 {
   try
   {
-    QString sql = QString( "SELECT %1" ).arg( quotedPrimaryKey() );
+    QString sql = QString( "SELECT %1" ).arg( mHasPrimaryKey ? quotedPrimaryKey() : "0" );
     int colIdx = 1; // column 0 is primary key
 
     if ( mRequest.flags() & QgsFeatureRequest::SubsetOfAttributes )
@@ -320,10 +323,19 @@ bool QgsSpatiaLiteFeatureIterator::getFeature( sqlite3_stmt *stmt, QgsFeature &f
   {
     if ( ic == 0 )
     {
-      // first column always contains the ROWID (or the primary key)
-      QgsFeatureId fid = sqlite3_column_int64( stmt, ic );
-      QgsDebugMsgLevel( QString( "fid=%1" ).arg( fid ), 3 );
-      feature.setFeatureId( fid );
+      if ( mHasPrimaryKey )
+      {
+        // first column always contains the ROWID (or the primary key)
+        QgsFeatureId fid = sqlite3_column_int64( stmt, ic );
+        QgsDebugMsgLevel( QString( "fid=%1" ).arg( fid ), 3 );
+        feature.setFeatureId( fid );
+      }
+      else
+      {
+        // autoincrement a row number
+        mRowNumber++;
+        feature.setFeatureId( mRowNumber );
+      }
     }
     else if ( mFetchGeometry && ic == mGeomColIdx )
     {

src/providers/spatialite/qgsspatialitefeatureiterator.h

@@ -93,6 +93,9 @@ class QgsSpatiaLiteFeatureIterator : public QgsAbstractFeatureIteratorFromSource
 
     //! Set to true, if geometry is in the requested columns
     bool mFetchGeometry;
+
+    bool mHasPrimaryKey;
+    QgsFeatureId mRowNumber;
 };
 
 #endif // QGSSPATIALITEFEATUREITERATOR_H

src/providers/spatialite/qgsspatialiteprovider.cpp

@@ -497,7 +497,7 @@ QgsSpatiaLiteProvider::QgsSpatiaLiteProvider( QString const &uri )
     closeDb();
     return;
   }
-  enabledCapabilities = QgsVectorDataProvider::SelectAtId | QgsVectorDataProvider::SelectGeometryAtId;
+  enabledCapabilities = mPrimaryKey.isEmpty() ? 0 : (QgsVectorDataProvider::SelectAtId | QgsVectorDataProvider::SelectGeometryAtId);
   if (( mTableBased || mViewBased ) &&  !mReadOnly )
   {
     // enabling editing only for Tables [excluding Views and VirtualShapes]

tests/src/python/test_qgsspatialiteprovider.py

@@ -76,10 +76,10 @@ def setUpClass(cls):
         sql = "SELECT AddGeometryColumn('test_q', 'geometry', 4326, 'POLYGON', 'XY')"
         cur.execute(sql)
         sql = "INSERT INTO test_q (id, name, geometry) "
-        sql +=    "VALUES (1, 'toto', GeomFromText('POLYGON((0 0,1 0,1 1,0 1,0 0))', 4326))"
+        sql +=    "VALUES (11, 'toto', GeomFromText('POLYGON((0 0,1 0,1 1,0 1,0 0))', 4326))"
         cur.execute(sql)
         sql = "INSERT INTO test_q (id, name, geometry) "
-        sql +=    "VALUES (2, 'toto', GeomFromText('POLYGON((0 0,1 0,1 1,0 1,0 0))', 4326))"
+        sql +=    "VALUES (21, 'toto', GeomFromText('POLYGON((0 0,1 0,1 1,0 1,0 0))', 4326))"
         cur.execute(sql)
 
         # simple table with a geometry column named 'Geometry'
@@ -150,32 +150,31 @@ def test_queries(self):
         """Test loading of query-based layers"""
 
         # a query with a geometry, but no unique id
-        # this allows to load a query without unique id
-        # however, functions relying on such a unique id would fail
+        # the id will be autoincremented
         l = QgsVectorLayer("dbname=%s table='(select * from test_q)' (geometry)" % self.dbname, "test_pg_query1", "spatialite")
         assert(l.isValid())
-        # the id() is not consistent
+        # the id() is autoincremented
         sum_id1 = sum(f.id() for f in l.getFeatures())
         # the attribute 'id' works
         sum_id2 = sum(f.attributes()[0] for f in l.getFeatures())
-        assert(sum_id1 == 0)
-        assert(sum_id2 == 3)
+        assert(sum_id1 == 3) # 1+2
+        assert(sum_id2 == 32) # 11 + 21
 
         # and now with an id declared
         l = QgsVectorLayer("dbname=%s table='(select * from test_q)' (geometry) key='id'" % self.dbname, "test_pg_query1", "spatialite")
         assert(l.isValid())
         sum_id1 = sum(f.id() for f in l.getFeatures())
         sum_id2 = sum(f.attributes()[0] for f in l.getFeatures())
-        assert(sum_id1 == 3)
-        assert(sum_id2 == 3)
+        assert(sum_id1 == 32)
+        assert(sum_id2 == 32)
 
         # a query, but no geometry
         l = QgsVectorLayer("dbname=%s table='(select id,name from test_q)' key='id'" % self.dbname, "test_pg_query1", "spatialite")
         assert(l.isValid())
         sum_id1 = sum(f.id() for f in l.getFeatures())
         sum_id2 = sum(f.attributes()[0] for f in l.getFeatures())
-        assert(sum_id1 == 3)
-        assert(sum_id2 == 3)
+        assert(sum_id1 == 32)
+        assert(sum_id2 == 32)
 
     def test_case(self):
         """Test case sensitivity issues"""