diff --git a/src/providers/postgres/qgspostgresprovider.cpp b/src/providers/postgres/qgspostgresprovider.cpp
index a891dd7dcc0..1d68f00a6be 100644
--- a/src/providers/postgres/qgspostgresprovider.cpp
+++ b/src/providers/postgres/qgspostgresprovider.cpp
@@ -1285,11 +1285,9 @@ bool QgsPostgresProvider::determinePrimaryKey()
       // If the relation is a view try to find a suitable column to use as
       // the primary key.
 
-      sql = QStringLiteral( "SELECT relkind FROM pg_class WHERE oid=regclass(%1)::oid" ).arg( quotedValue( mQuery ) );
-      res = connectionRO()->PQexec( sql );
-      QString type = res.PQgetvalue( 0, 0 );
+      QgsPostgresProvider::Relkind type = relkind();
 
-      if ( type == QLatin1String( "r" ) ) // the relation is a table
+      if ( type == Relkind::OrdinaryTable )
       {
         QgsDebugMsg( "Relation is a table. Checking to see if it has an oid column." );
 
@@ -1324,13 +1322,15 @@ bool QgsPostgresProvider::determinePrimaryKey()
           }
         }
       }
-      else if ( type == QLatin1String( "v" ) || type == QLatin1String( "m" ) ) // the relation is a view
+      else if ( type == Relkind::View || type == Relkind::MaterializedView )
       {
         determinePrimaryKeyFromUriKeyColumn();
       }
       else
       {
-        QgsMessageLog::logMessage( tr( "Unexpected relation type '%1'." ).arg( type ), tr( "PostGIS" ) );
+        const QMetaEnum metaEnum( QMetaEnum::fromType<Relkind>() );
+        QString typeName = metaEnum.valueToKey( type );
+        QgsMessageLog::logMessage( tr( "Unexpected relation type '%1'." ).arg( typeName ), tr( "PostGIS" ) );
       }
     }
     else
@@ -4247,6 +4247,50 @@ QgsAttrPalIndexNameHash QgsPostgresProvider::palAttributeIndexNames() const
   return mAttrPalIndexName;
 }
 
+QgsPostgresProvider::Relkind QgsPostgresProvider::relkind() const
+{
+  QString sql = QStringLiteral( "SELECT relkind FROM pg_class WHERE oid=regclass(%1)::oid" ).arg( quotedValue( mQuery ) );
+  QgsPostgresResult res( connectionRO()->PQexec( sql ) );
+  QString type = res.PQgetvalue( 0, 0 );
+
+  QgsPostgresProvider::Relkind kind = Relkind::Unknown;
+
+  if ( type == QLatin1String( "r" ) )
+  {
+    kind = Relkind::OrdinaryTable;
+  }
+  else if ( type == QLatin1String( "i" ) )
+  {
+    kind = Relkind::Index;
+  }
+  else if ( type == QLatin1String( "s" ) )
+  {
+    kind = Relkind::Sequence;
+  }
+  else if ( type == QLatin1String( "v" ) )
+  {
+    kind = Relkind::View;
+  }
+  else if ( type == QLatin1String( "m" ) )
+  {
+    kind = Relkind::MaterializedView;
+  }
+  else if ( type == QLatin1String( "c" ) )
+  {
+    kind = Relkind::CompositeType;
+  }
+  else if ( type == QLatin1String( "t" ) )
+  {
+    kind = Relkind::ToastTable;
+  }
+  else if ( type == QLatin1String( "f" ) )
+  {
+    kind = Relkind::ForeignTable;
+  }
+
+  return kind;
+}
+
 /**
  * Class factory to return a pointer to a newly created
  * QgsPostgresProvider object
diff --git a/src/providers/postgres/qgspostgresprovider.h b/src/providers/postgres/qgspostgresprovider.h
index 9a264a9f92f..959f34dff5d 100644
--- a/src/providers/postgres/qgspostgresprovider.h
+++ b/src/providers/postgres/qgspostgresprovider.h
@@ -48,6 +48,19 @@ class QgsPostgresProvider : public QgsVectorDataProvider
     Q_OBJECT
 
   public:
+    enum Relkind
+    {
+      Unknown,
+      OrdinaryTable, // r
+      Index, // i
+      Sequence, // s
+      View, // v
+      MaterializedView, // m
+      CompositeType, // c
+      ToastTable, // t
+      ForeignTable // f
+    };
+    Q_ENUM( Relkind );
 
     /** Import a vector layer into the database
      * \param options options for provider, specified via a map of option name
@@ -206,6 +219,7 @@ class QgsPostgresProvider : public QgsVectorDataProvider
     void repaintRequested();
 
   private:
+    Relkind relkind() const;
 
     bool declareCursor( const QString &cursorName,
                         const QgsAttributeList &fetchAttributes,