diff --git a/examples/KReportExampleData.h b/examples/KReportExampleData.h
--- a/examples/KReportExampleData.h
+++ b/examples/KReportExampleData.h
@@ -20,18 +20,18 @@
 #ifndef KREPORTEXAMPLEDATA_H
 #define KREPORTEXAMPLEDATA_H
 
-#include <KReportData>
+#include <KReportDataSource>
 #include <QVariant>
 #include <QStringList>
 #include <QList>
 
-class KReportExampleData : public KReportData
+class KReportExampleData : public KReportDataSource
 {
 public:
     KReportExampleData();
     ~KReportExampleData();
     virtual QVariant value(const QString& field) const;
-    virtual QVariant value(unsigned int) const;
+    virtual QVariant value(int) const;
     virtual QStringList fieldNames() const;
     virtual QStringList fieldKeys() const;
     virtual int fieldNumber(const QString& field) const;
@@ -46,6 +46,8 @@
 
     virtual QStringList scriptList() const;
     virtual QString scriptCode(const QString &script) const;
+    
+    virtual QStringList dataSourceNames() const;
 
 private:
     struct Data
diff --git a/examples/KReportExampleData.cpp b/examples/KReportExampleData.cpp
--- a/examples/KReportExampleData.cpp
+++ b/examples/KReportExampleData.cpp
@@ -41,7 +41,7 @@
     return value(fieldNumber(field));
 }
 
-QVariant KReportExampleData::value(unsigned int f) const
+QVariant KReportExampleData::value(int f) const
 {
     switch(f) {
         case 0:
@@ -190,3 +190,8 @@
 
     return scriptcode;
 }
+
+QStringList KReportExampleData::dataSourceNames() const
+{
+    return QStringList();
+}
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -21,7 +21,7 @@
     common/KReportPluginManager.cpp
     common/KReportJsonTrader_p.cpp
     common/KReportPluginMetaData.cpp
-    common/KReportData.cpp
+    common/KReportDataSource.cpp
     common/KReportUtils.cpp
     common/KReportPageSize.cpp
     common/KReportUnit.cpp
@@ -254,7 +254,7 @@
     RELATIVE common
     HEADER_NAMES
         KReportPageSize
-        KReportData
+        KReportDataSource
         KReportItemBase
         KReportItemLine
         KReportPluginMetaData
diff --git a/src/common/KReportData.h b/src/common/KReportDataSource.h
rename from src/common/KReportData.h
rename to src/common/KReportDataSource.h
--- a/src/common/KReportData.h
+++ b/src/common/KReportDataSource.h
@@ -25,12 +25,12 @@
 
 /** @brief Abstraction of report data source
 */
-class KREPORT_EXPORT KReportData
+class KREPORT_EXPORT KReportDataSource
 {
 
 public:
-    KReportData();
-    virtual ~KReportData();
+    KReportDataSource();
+    virtual ~KReportDataSource();
 
     //! Describes sorting for single field
     /*! By default the order is ascending. */
@@ -87,7 +87,7 @@
     virtual QStringList fieldKeys() const;
 
     //! Return the value of the field at the given position for the current record
-    virtual QVariant value(unsigned int) const = 0;
+    virtual QVariant value(int) const = 0;
 
     //! Return the value of the field fir the given name for the current record
     virtual QVariant value(const QString &field) const = 0;
@@ -104,7 +104,7 @@
     virtual void setSorting(const QList<SortedField> &sorting);
 
     //! Adds an expression to the data source
-    virtual void addExpression(const QString &field, const QVariant &value, char relation = '=');
+    virtual void addCondition(const QString &field, const QVariant &value, char relation = '=');
 
     //! Utility Functions
     //! @todo These are probably eligable to be moved into a new class
@@ -118,20 +118,22 @@
     virtual QString scriptCode(const QString& script) const;
 #endif
 
-    //! Return a list of data sources possible for advanced controls
-    virtual QStringList dataSources() const;
+    //! Return a list of data source names available for this data source
+    //! Works after the source is opened
+    virtual QStringList dataSourceNames() const = 0;
 
-    //! Return a list of data source names possible for advanced controls.
-    //! Returns dataSources() by default
-    virtual QStringList dataSourceNames() const;
+    //! Return data source caption for specified @a dataSourceName
+    //! It is possibly translated. As such it is suitable for use in GUIs.
+    //! Default implementation just returns @a dataSourceName.
+    virtual QString dataSourceCaption(const QString &dataSourceName) const;
 
     //! Creates a new instance with data source. Default implementation returns @c nullptr.
     //! @a source is implementation-specific identifier.
     //! Owner of the returned pointer is the caller.
-    virtual KReportData* create(const QString &source) const Q_REQUIRED_RESULT;
+    virtual KReportDataSource* create(const QString &source) const Q_REQUIRED_RESULT;
     
 private:
-    Q_DISABLE_COPY(KReportData)
+    Q_DISABLE_COPY(KReportDataSource)
     class Private;
     Private * const d;
 };
diff --git a/src/common/KReportData.cpp b/src/common/KReportDataSource.cpp
rename from src/common/KReportData.cpp
rename to src/common/KReportDataSource.cpp
--- a/src/common/KReportData.cpp
+++ b/src/common/KReportDataSource.cpp
@@ -15,12 +15,12 @@
  * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "KReportData.h"
+#include "KReportDataSource.h"
 #include <QVariant>
 
 #define KReportDataSortedFieldPrivateArgs(o) std::tie(o.field, o.order)
 
-class KReportData::SortedField::Private 
+class KReportDataSource::SortedField::Private 
 {
     
 public:
@@ -32,131 +32,131 @@
     Qt::SortOrder order = Qt::AscendingOrder;
 };
 
-class KReportData::Private
+class KReportDataSource::Private
 {
 public:
     bool dummy = true;
 };
 
 //==========KReportData::SortedField==========
 
-KReportData::SortedField::SortedField()
+KReportDataSource::SortedField::SortedField()
     : d(new Private)
 {
 }
 
-KReportData::SortedField::SortedField(const KReportData::SortedField& other) : d(new Private(*other.d))
+KReportDataSource::SortedField::SortedField(const KReportDataSource::SortedField& other) : d(new Private(*other.d))
 {
 }
 
 
-KReportData::SortedField::~SortedField()
+KReportDataSource::SortedField::~SortedField()
 {
     delete d;
 }
 
-KReportData::SortedField & KReportData::SortedField::operator=(const KReportData::SortedField& other)
+KReportDataSource::SortedField & KReportDataSource::SortedField::operator=(const KReportDataSource::SortedField& other)
 {
     if (this != &other) {
         setField(other.field());
         setOrder(other.order());
     }
     return *this;
 }
 
-bool KReportData::SortedField::operator==(const KReportData::SortedField& other) const
+bool KReportDataSource::SortedField::operator==(const KReportDataSource::SortedField& other) const
 {
     return KReportDataSortedFieldPrivateArgs((*d)) == KReportDataSortedFieldPrivateArgs((*other.d));
 }
 
-bool KReportData::SortedField::operator!=(const KReportData::SortedField& other) const
+bool KReportDataSource::SortedField::operator!=(const KReportDataSource::SortedField& other) const
 {
     return KReportDataSortedFieldPrivateArgs((*d)) != KReportDataSortedFieldPrivateArgs((*other.d));
 }
 
-QString KReportData::SortedField::field() const
+QString KReportDataSource::SortedField::field() const
 {
     return d->field;
 }
 
-Qt::SortOrder KReportData::SortedField::order() const
+Qt::SortOrder KReportDataSource::SortedField::order() const
 {
     return d->order;
 }
 
-void KReportData::SortedField::setField(const QString& field)
+void KReportDataSource::SortedField::setField(const QString& field)
 {
     d->field = field;
 }
 
-void KReportData::SortedField::setOrder(Qt::SortOrder order)
+void KReportDataSource::SortedField::setOrder(Qt::SortOrder order)
 {
     d->order = order;
 }
 
 
 //==========KReportData==========
 
-KReportData::KReportData() : d(new Private())
+KReportDataSource::KReportDataSource() : d(new Private())
 {
 }
 
-KReportData::~KReportData()
+KReportDataSource::~KReportDataSource()
 {
     delete d;
 }
 
-QStringList KReportData::fieldKeys() const
+QStringList KReportDataSource::fieldKeys() const
 {
     return fieldNames();
 }
 
-QString KReportData::sourceName() const
+QString KReportDataSource::sourceName() const
 {
     return QString();
 }
 
-QString KReportData::sourceClass() const
+QString KReportDataSource::sourceClass() const
 {
     return QString();
 }
 
-void KReportData::setSorting(const QList<SortedField> &sorting)
+void KReportDataSource::setSorting(const QList<SortedField> &sorting)
 {
     Q_UNUSED(sorting);
 }
 
-void KReportData::addExpression(const QString &field, const QVariant &value, char relation)
+void KReportDataSource::addCondition(const QString &field, const QVariant &value, char relation)
 {
     Q_UNUSED(field);
     Q_UNUSED(value);
     Q_UNUSED(relation);
 }
 
 #ifdef KREPORT_SCRIPTING
-QStringList KReportData::scriptList() const
+QStringList KReportDataSource::scriptList() const
 {
     return QStringList();
 }
 
-QString KReportData::scriptCode(const QString &script) const
+QString KReportDataSource::scriptCode(const QString &script) const
 {
     Q_UNUSED(script);
     return QString();
 }
 #endif
 
-QStringList KReportData::dataSources() const
+QStringList KReportDataSource::dataSourceNames() const
 {
     return QStringList();
 }
 
-QStringList KReportData::dataSourceNames() const
+QString KReportDataSource::dataSourceCaption(const QString &dataSourceName) const
 {
-    return dataSources();
+    return dataSourceName;
 }
 
-KReportData* KReportData::create(const QString &source) const
+KReportDataSource* KReportDataSource::create(const QString &source) const
 {
     Q_UNUSED(source);
     return 0;
diff --git a/src/common/KReportDetailSectionData.h b/src/common/KReportDetailSectionData.h
--- a/src/common/KReportDetailSectionData.h
+++ b/src/common/KReportDetailSectionData.h
@@ -21,7 +21,7 @@
 
 #include <QObject>
 
-#include "KReportData.h"
+#include "KReportDataSource.h"
 
 class KReportSectionData;
 class KReportDetailGroupSectionData;
@@ -46,7 +46,7 @@
 
     QString m_name;
     int m_pageBreak;
-    QList<KReportData::SortedField> m_sortedFields;
+    QList<KReportDataSource::SortedField> m_sortedFields;
 
     KReportSectionData * m_detailSection;
 
diff --git a/src/common/KReportDetailSectionData.cpp b/src/common/KReportDetailSectionData.cpp
--- a/src/common/KReportDetailSectionData.cpp
+++ b/src/common/KReportDetailSectionData.cpp
@@ -90,7 +90,7 @@
                 }
             }
             m_groupList.append(dgsd);
-            KReportData::SortedField s;
+            KReportDataSource::SortedField s;
             s.setField(dgsd->m_column);
             s.setOrder(dgsd->m_sort);
             m_sortedFields.append(s);
diff --git a/src/common/KReportItemBase.h b/src/common/KReportItemBase.h
--- a/src/common/KReportItemBase.h
+++ b/src/common/KReportItemBase.h
@@ -29,7 +29,7 @@
 class OROPage;
 class OROSection;
 class KReportSize;
-class KReportData;
+class KReportDataSource;
 class KReportLineStyle;
 
 #ifdef KREPORT_SCRIPTING
@@ -90,7 +90,7 @@
     @brief Render a complex item that uses a sub query as a data source
     @return the height required by the object
     */
-    virtual int renderReportData(OROPage *page, OROSection *section, const QPointF &offset, KReportData *data, KReportScriptHandler *script);
+    virtual int renderReportData(OROPage *page, OROSection *section, const QPointF &offset, KReportDataSource *data, KReportScriptHandler *script);
 
     /**
     @brief Override if the item supports a simple data source, such as a field
diff --git a/src/common/KReportItemBase.cpp b/src/common/KReportItemBase.cpp
--- a/src/common/KReportItemBase.cpp
+++ b/src/common/KReportItemBase.cpp
@@ -116,7 +116,7 @@
 }
 
 int KReportItemBase::renderReportData(OROPage *page, OROSection *section, const QPointF &offset,
-                                       KReportData *data, KReportScriptHandler* script)
+                                       KReportDataSource *data, KReportScriptHandler* script)
 {
     Q_UNUSED(page)
     Q_UNUSED(section)
diff --git a/src/common/KReportRenderObjects.h b/src/common/KReportRenderObjects.h
--- a/src/common/KReportRenderObjects.h
+++ b/src/common/KReportRenderObjects.h
@@ -29,7 +29,7 @@
 #include <QPicture>
 #include <QPageLayout>
 
-#include "KReportData.h"
+#include "KReportDataSource.h"
 #include "KReportItemBase.h"
 #include "KReportSectionData.h"
 #include "KReportLineStyle.h"
diff --git a/src/plugins/web/KReportItemWeb.h b/src/plugins/web/KReportItemWeb.h
--- a/src/plugins/web/KReportItemWeb.h
+++ b/src/plugins/web/KReportItemWeb.h
@@ -22,7 +22,7 @@
 #define KREPORTITEMWEB_H
 
 #include "KReportAsyncItemBase.h"
-#include "KReportData.h"
+#include "KReportDataSource.h"
 
 #include <QGraphicsScene>
 #include <QUrl>
diff --git a/src/renderer/KReportOneRecordData_p.h b/src/renderer/KReportOneRecordData_p.h
--- a/src/renderer/KReportOneRecordData_p.h
+++ b/src/renderer/KReportOneRecordData_p.h
@@ -22,7 +22,7 @@
 #ifndef KREPORTONERECORDDATA_H
 #define KREPORTONERECORDDATA_H
 
-#include <KReportData.h>
+#include <KReportDataSource.h>
 
 namespace KReportPrivate {
 /**
@@ -34,13 +34,13 @@
  * a report with a static page of data, or a report page
  * generated from a script only.
  */
-class OneRecordData :  public KReportData
+class OneRecordData :  public KReportDataSource
 {
 public:
     OneRecordData();
     ~OneRecordData();
     virtual QVariant value(const QString& field) const;
-    virtual QVariant value(unsigned int fieldNum) const;
+    virtual QVariant value(int fieldNum) const;
     virtual QStringList fieldNames() const;
     virtual int fieldNumber(const QString& field) const;
     virtual qint64 recordCount() const;
@@ -51,6 +51,7 @@
     virtual bool moveNext();
     virtual bool close();
     virtual bool open();
+    virtual QStringList dataSourceNames() const;
 };
 }
 
diff --git a/src/renderer/KReportOneRecordData_p.cpp b/src/renderer/KReportOneRecordData_p.cpp
--- a/src/renderer/KReportOneRecordData_p.cpp
+++ b/src/renderer/KReportOneRecordData_p.cpp
@@ -38,7 +38,7 @@
     return QVariant();
 }
 
-QVariant OneRecordData::value(unsigned int fieldNum) const
+QVariant OneRecordData::value(int fieldNum) const
 {
     Q_UNUSED(fieldNum);
     return QVariant();
@@ -95,4 +95,9 @@
     return true;
 }
 
-}
\ No newline at end of file
+QStringList OneRecordData::dataSourceNames() const
+{
+    return QStringList();
+}
+
+}
diff --git a/src/renderer/KReportPreRenderer.h b/src/renderer/KReportPreRenderer.h
--- a/src/renderer/KReportPreRenderer.h
+++ b/src/renderer/KReportPreRenderer.h
@@ -31,7 +31,7 @@
 #endif
 class KReportPreRendererPrivate;
 class ORODocument;
-class KReportData;
+class KReportDataSource;
 class KReportDocument;
 class QDomElement;
 
@@ -49,7 +49,7 @@
     virtual ~KReportPreRenderer();
 
     //! Sets source data to @a data, takes ownership
-    void setSourceData(KReportData* data);
+    void setSourceData(KReportDataSource* data);
 
 #ifdef KREPORT_SCRIPTING
     KReportScriptHandler *scriptHandler();
diff --git a/src/renderer/KReportPreRenderer.cpp b/src/renderer/KReportPreRenderer.cpp
--- a/src/renderer/KReportPreRenderer.cpp
+++ b/src/renderer/KReportPreRenderer.cpp
@@ -22,7 +22,7 @@
 #include "KReportOneRecordData_p.h"
 
 #include "KReportRenderObjects.h"
-#include "KReportData.h"
+#include "KReportDataSource.h"
 #include "KReportItemBase.h"
 #include "KReportDocument.h"
 #include "KReportDetailSectionData.h"
@@ -529,7 +529,7 @@
 
         KReportDetailSectionData * detailData = m_reportDocument->m_detailSection;
         if (detailData->m_detailSection) {
-            KReportData *mydata = m_kodata;
+            KReportDataSource *mydata = m_kodata;
 
             if (mydata && mydata->recordCount() > 0) { /* && !((query = orqThis->getQuery())->eof()))*/
                 if (!mydata->moveFirst()) {
@@ -655,7 +655,7 @@
     return d->m_document;
 }
 
-void KReportPreRenderer::setSourceData(KReportData *data)
+void KReportPreRenderer::setSourceData(KReportDataSource *data)
 {
     if (d && data != d->m_kodata) {
         delete d->m_kodata;
diff --git a/src/renderer/KReportPreRenderer_p.h b/src/renderer/KReportPreRenderer_p.h
--- a/src/renderer/KReportPreRenderer_p.h
+++ b/src/renderer/KReportPreRenderer_p.h
@@ -59,7 +59,7 @@
     qreal m_maxWidth;     // -- same as above --
     int m_pageCounter;    // what page are we currently on?
 
-    KReportData* m_kodata;
+    KReportDataSource* m_kodata;
     KReportPrivate::OneRecordData *m_oneRecord;
 
     QList<OROTextBox*> m_postProcText;
diff --git a/src/renderer/scripting/KReportScriptHandler.h b/src/renderer/scripting/KReportScriptHandler.h
--- a/src/renderer/scripting/KReportScriptHandler.h
+++ b/src/renderer/scripting/KReportScriptHandler.h
@@ -23,7 +23,7 @@
 
 #ifdef KREPORT_SCRIPTING
 #include "KReportScriptConstants.h"
-#include "KReportData.h"
+#include "KReportDataSource.h"
 #include <QtQml/QJSValue>
 
 class KReportScriptDebug;
@@ -43,7 +43,7 @@
 {
     Q_OBJECT
 public:
-    KReportScriptHandler(const KReportData *, KReportDocument*);
+    KReportScriptHandler(const KReportDataSource *, KReportDocument*);
     ~KReportScriptHandler();
 
     QVariant evaluate(const QString&);
diff --git a/src/renderer/scripting/KReportScriptHandler.cpp b/src/renderer/scripting/KReportScriptHandler.cpp
--- a/src/renderer/scripting/KReportScriptHandler.cpp
+++ b/src/renderer/scripting/KReportScriptHandler.cpp
@@ -43,7 +43,7 @@
     KReportScriptDebug *debug;
     KReportScriptDraw *draw;
     Scripting::Report *report;
-    const KReportData *reportData;
+    const KReportDataSource *reportData;
     QString source;
     KReportDocument  *reportDocument;
     QJSEngine engine;
@@ -60,7 +60,7 @@
 {
 }
 
-KReportScriptHandler::KReportScriptHandler(const KReportData* kodata, KReportDocument* doc) : d(new Private())
+KReportScriptHandler::KReportScriptHandler(const KReportDataSource* kodata, KReportDocument* doc) : d(new Private())
 {
     d->reportDocument = doc;
     d->reportData = kodata;
diff --git a/src/wrtembed/KReportDesigner.h b/src/wrtembed/KReportDesigner.h
--- a/src/wrtembed/KReportDesigner.h
+++ b/src/wrtembed/KReportDesigner.h
@@ -22,7 +22,7 @@
 #include <QWidget>
 
 #include "KReportDocument.h"
-#include "KReportData.h"
+#include "KReportDataSource.h"
 
 class KProperty;
 class KPropertySet;
@@ -72,15 +72,15 @@
     @brief Sets the report data
     The report data interface contains functions to retrieve data
     and information about the fields.
-    @param kodata Pointer to KReportData instance, ownership is transferred
+    @param kodata Pointer to KReportDataSource instance, ownership is transferred
     */
-    void setReportData(KReportData* kodata);
+    void setReportData(KReportDataSource* kodata);
 
     /**
     @brief Return a pointer to the reports data
     @return Pointer to report data
     */
-    KReportData *reportData() const;
+    KReportDataSource *reportData() const;
 
     /**
     @brief Return a pointer to the section specified
diff --git a/src/wrtembed/KReportDesigner.cpp b/src/wrtembed/KReportDesigner.cpp
--- a/src/wrtembed/KReportDesigner.cpp
+++ b/src/wrtembed/KReportDesigner.cpp
@@ -182,7 +182,7 @@
     QString originalInterpreter; //Value of the script interpreter at load time
     QString originalScript; //Value of the script at load time
 
-    KReportData *kordata = nullptr;
+    KReportDataSource *kordata = nullptr;
 };
 
 KReportDesigner::KReportDesigner(QWidget * parent)
@@ -441,7 +441,7 @@
     (void)se.exec();
 }
 
-void KReportDesigner::setReportData(KReportData* kodata)
+void KReportDesigner::setReportData(KReportDataSource* kodata)
 {
     if (d->kordata == kodata) {
         return;
@@ -648,7 +648,7 @@
     return d->itmset;
 }
 
-KReportData *KReportDesigner::reportData() const
+KReportDataSource *KReportDesigner::reportData() const
 {
     return d->kordata;
 }