diff --git a/src/CreateIndexDialog.cpp b/src/CreateIndexDialog.cpp
index ee5babf3..33bd5e6c 100644
--- a/src/CreateIndexDialog.cpp
+++ b/src/CreateIndexDialog.cpp
@@ -23,7 +23,7 @@ CreateIndexDialog::~CreateIndexDialog()
     delete ui;
 }
 
-void CreateIndexDialog::tableChanged(QString new_table)
+void CreateIndexDialog::tableChanged(const QString& new_table)
 {
     // And fill the table again
     QStringList fields = pdb->getTableFields(new_table);
diff --git a/src/CreateIndexDialog.h b/src/CreateIndexDialog.h
index 52eb36a3..6bad3d4f 100644
--- a/src/CreateIndexDialog.h
+++ b/src/CreateIndexDialog.h
@@ -18,7 +18,7 @@ public:
 
 private slots:
     void accept();
-    void tableChanged(QString new_table);
+    void tableChanged(const QString& new_table);
     void checkInput();
 
 private:
diff --git a/src/EditDialog.cpp b/src/EditDialog.cpp
index 5147297b..ff4a0686 100644
--- a/src/EditDialog.cpp
+++ b/src/EditDialog.cpp
@@ -57,7 +57,7 @@ void EditDialog::closeEvent(QCloseEvent*)
     emit goingAway();
 }
 
-void EditDialog::loadText(QString  text, int row, int col)
+void EditDialog::loadText(const QString&  text, int row, int col)
 {
     ui->editData->setPlainText(text);
     ui->editData->setFocus();
diff --git a/src/EditDialog.h b/src/EditDialog.h
index f5ef183f..aa8bff2b 100644
--- a/src/EditDialog.h
+++ b/src/EditDialog.h
@@ -23,7 +23,7 @@ public:
 
 public slots:
     virtual void reset();
-    virtual void loadText(QString text, int row, int col);
+    virtual void loadText(const QString& text, int row, int col);
 
 private slots:
     virtual void enableExport(bool enabled);
@@ -37,7 +37,7 @@ private slots:
 
 signals:
     void goingAway();
-    void updateRecordText(int, int, QString);
+    void updateRecordText(int, int, const QString&);
 
 private:
     Ui::EditDialog* ui;
diff --git a/src/EditFieldDialog.cpp b/src/EditFieldDialog.cpp
index 963418b8..f6022412 100644
--- a/src/EditFieldDialog.cpp
+++ b/src/EditFieldDialog.cpp
@@ -4,7 +4,7 @@
 #include <QPushButton>
 #include <QMessageBox>
 
-EditFieldDialog::EditFieldDialog(DBBrowserDB* db, bool new_field, QString table, QString fld_name, QString fld_type, QWidget* parent)
+EditFieldDialog::EditFieldDialog(DBBrowserDB* db, bool new_field, const QString& table, const QString& fld_name, const QString& fld_type, QWidget* parent)
     : QDialog(parent),
       ui(new Ui::EditFieldDialog),
       pdb(db),
diff --git a/src/EditFieldDialog.h b/src/EditFieldDialog.h
index 1d849431..50080959 100644
--- a/src/EditFieldDialog.h
+++ b/src/EditFieldDialog.h
@@ -14,7 +14,7 @@ class EditFieldDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit EditFieldDialog(DBBrowserDB* db, bool new_field, QString table, QString fld_name, QString fld_type, QWidget* parent = 0);
+    explicit EditFieldDialog(DBBrowserDB* db, bool new_field, const QString& table, const QString& fld_name, const QString& fld_type, QWidget* parent = 0);
     ~EditFieldDialog();
 
     QString getFieldName() { return field_name; }
diff --git a/src/EditTableDialog.cpp b/src/EditTableDialog.cpp
index 88a42924..41b30d06 100644
--- a/src/EditTableDialog.cpp
+++ b/src/EditTableDialog.cpp
@@ -5,7 +5,7 @@
 #include <QPushButton>
 #include "sqlitedb.h"
 
-EditTableDialog::EditTableDialog(DBBrowserDB* db, QString tableName, QWidget* parent)
+EditTableDialog::EditTableDialog(DBBrowserDB* db, const QString& tableName, QWidget* parent)
     : QDialog(parent),
       ui(new Ui::EditTableDialog),
       pdb(db),
diff --git a/src/EditTableDialog.h b/src/EditTableDialog.h
index 0cd29b7c..40711776 100644
--- a/src/EditTableDialog.h
+++ b/src/EditTableDialog.h
@@ -13,7 +13,7 @@ class EditTableDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit EditTableDialog(DBBrowserDB* pdb, QString tableName, QWidget* parent = 0);
+    explicit EditTableDialog(DBBrowserDB* pdb, const QString& tableName, QWidget* parent = 0);
     ~EditTableDialog();
 
 private slots:
diff --git a/src/ExportCsvDialog.cpp b/src/ExportCsvDialog.cpp
index c964fd1a..90a3d804 100644
--- a/src/ExportCsvDialog.cpp
+++ b/src/ExportCsvDialog.cpp
@@ -6,7 +6,7 @@
 #include "ui_ExportCsvDialog.h"
 #include "sqlitedb.h"
 
-ExportCsvDialog::ExportCsvDialog(DBBrowserDB* db, QString deflocation, QWidget* parent)
+ExportCsvDialog::ExportCsvDialog(DBBrowserDB* db, const QString& deflocation, QWidget* parent)
     : QDialog(parent),
       ui(new Ui::ExportCsvDialog),
       pdb(db),
diff --git a/src/ExportCsvDialog.h b/src/ExportCsvDialog.h
index 55db7637..aae69395 100644
--- a/src/ExportCsvDialog.h
+++ b/src/ExportCsvDialog.h
@@ -13,7 +13,7 @@ class ExportCsvDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit ExportCsvDialog(DBBrowserDB* db, QString deflocation, QWidget* parent = 0);
+    explicit ExportCsvDialog(DBBrowserDB* db, const QString& deflocation, QWidget* parent = 0);
     ~ExportCsvDialog();
 
 private slots:
diff --git a/src/FindDialog.cpp b/src/FindDialog.cpp
index 9c8582e8..ade4c713 100644
--- a/src/FindDialog.cpp
+++ b/src/FindDialog.cpp
@@ -13,11 +13,11 @@ FindDialog::~FindDialog()
     delete ui;
 }
 
-void FindDialog::showResults(resultMap rmap)
+void FindDialog::showResults(const resultMap& rmap)
 {
     ui->tableResults->setSortingEnabled(false);
     ui->tableResults->clearContents();
-    resultMap::Iterator it;
+    resultMap::const_iterator it;
     int rowNum;
     ui->tableResults->setRowCount(rmap.size());
     for(it=rmap.begin(),rowNum=0;it!=rmap.end();++it,rowNum++)
@@ -36,7 +36,7 @@ void FindDialog::find()
     emit lookfor(ui->comboColumn->currentText(), ui->comboOperator->currentText(), ui->editSearchString->text());
 }
 
-void FindDialog::resetFields(QStringList fieldlist)
+void FindDialog::resetFields(const QStringList& fieldlist)
 {
     ui->comboColumn->clear();
     ui->comboColumn->addItems(fieldlist);
diff --git a/src/FindDialog.h b/src/FindDialog.h
index 6ec929c0..46b0eef1 100644
--- a/src/FindDialog.h
+++ b/src/FindDialog.h
@@ -18,8 +18,8 @@ public:
     ~FindDialog();
 
 public slots:
-    virtual void showResults(resultMap rmap);
-    virtual void resetFields(QStringList fieldlist = QStringList());
+    virtual void showResults(const resultMap& rmap);
+    virtual void resetFields(const QStringList& fieldlist = QStringList());
 
 private slots:
     virtual void find();
diff --git a/src/ImportCsvDialog.cpp b/src/ImportCsvDialog.cpp
index 9147766d..5f61d323 100644
--- a/src/ImportCsvDialog.cpp
+++ b/src/ImportCsvDialog.cpp
@@ -5,7 +5,7 @@
 #include <QPushButton>
 #include "sqlitedb.h"
 
-ImportCsvDialog::ImportCsvDialog(QString filename, DBBrowserDB* db, QWidget* parent)
+ImportCsvDialog::ImportCsvDialog(const QString& filename, DBBrowserDB* db, QWidget* parent)
     : QDialog(parent),
       ui(new Ui::ImportCsvDialog),
       csvFilename(filename),
diff --git a/src/ImportCsvDialog.h b/src/ImportCsvDialog.h
index 821b53e6..3e8f66a9 100644
--- a/src/ImportCsvDialog.h
+++ b/src/ImportCsvDialog.h
@@ -13,7 +13,7 @@ class ImportCsvDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit ImportCsvDialog(QString filename, DBBrowserDB* db, QWidget* parent = 0);
+    explicit ImportCsvDialog(const QString& filename, DBBrowserDB* db, QWidget* parent = 0);
     ~ImportCsvDialog();
 
 private slots:
diff --git a/src/MainWindow.cpp b/src/MainWindow.cpp
index 5762422e..e867fa2a 100644
--- a/src/MainWindow.cpp
+++ b/src/MainWindow.cpp
@@ -640,7 +640,7 @@ void MainWindow::helpAbout()
     dialog.exec();
 }
 
-void MainWindow::updateRecordText(int row, int col, QString newtext)
+void MainWindow::updateRecordText(int row, int col, const QString& newtext)
 {
     if (!db.updateRecord(row, col, newtext)){
         QMessageBox::information( this, QApplication::applicationName(), tr("Data could not be updated"));
diff --git a/src/MainWindow.h b/src/MainWindow.h
index daab7c85..c3174027 100644
--- a/src/MainWindow.h
+++ b/src/MainWindow.h
@@ -122,7 +122,7 @@ private slots:
     virtual void editTable();
     virtual void helpWhatsThis();
     virtual void helpAbout();
-    virtual void updateRecordText( int row, int col, QString newtext );
+    virtual void updateRecordText( int row, int col, const QString& newtext );
     virtual void editWinAway();
     virtual void editText( int row, int col );
     virtual void doubleClickTable( int row, int col );
diff --git a/src/sqlitedb.cpp b/src/sqlitedb.cpp
index 534c21fc..41ae8fe0 100644
--- a/src/sqlitedb.cpp
+++ b/src/sqlitedb.cpp
@@ -471,7 +471,7 @@ bool DBBrowserDB::browseTable( const QString & tablename, const QString& orderby
     return hasValidBrowseSet;
 }
 
-bool DBBrowserDB::createTable(QString name, const QList<DBBrowserField>& structure)
+bool DBBrowserDB::createTable(const QString& name, const QList<DBBrowserField>& structure)
 {
     // Build SQL statement
     QString sql = QString("CREATE TABLE `%1` (").arg(name);
@@ -484,13 +484,13 @@ bool DBBrowserDB::createTable(QString name, const QList<DBBrowserField>& structu
     return executeSQL(sql);
 }
 
-bool DBBrowserDB::createColumn(QString tablename, QString fieldname, QString fieldtype)
+bool DBBrowserDB::createColumn(const QString& tablename, const QString& fieldname, const QString& fieldtype)
 {
     QString sql = QString("ALTER TABLE `%1` ADD COLUMN `%2` %3").arg(tablename).arg(fieldname).arg(fieldtype);
     return executeSQL(sql);
 }
 
-bool DBBrowserDB::renameColumn(QString tablename, QString from, QString to, QString type)
+bool DBBrowserDB::renameColumn(const QString& tablename, const QString& from, const QString& to, const QString& type)
 {
     // NOTE: This function is working around the incomplete ALTER TABLE command in SQLite. If SQLite should fully support this command one day, this entire
     // function can be changed to executing something like this:
@@ -570,7 +570,7 @@ bool DBBrowserDB::renameColumn(QString tablename, QString from, QString to, QStr
     return true;
 }
 
-bool DBBrowserDB::dropColumn(QString tablename, QString column)
+bool DBBrowserDB::dropColumn(const QString& tablename, const QString& column)
 {
     // NOTE: This function is working around the incomplete ALTER TABLE command in SQLite. If SQLite should fully support this command one day, this entire
     // function can be changed to executing something like this:
@@ -653,7 +653,7 @@ bool DBBrowserDB::dropColumn(QString tablename, QString column)
     return true;
 }
 
-bool DBBrowserDB::renameTable(QString from_table, QString to_table)
+bool DBBrowserDB::renameTable(const QString& from_table, const QString& to_table)
 {
     QString sql = QString("ALTER TABLE `%1` RENAME TO `%2`").arg(from_table, to_table);
     if(!executeSQL(sql))
@@ -850,7 +850,7 @@ int DBBrowserDB::getRecordCount()
     return browseRecs.count();
 }
 
-void DBBrowserDB::logSQL(QString statement, int msgtype)
+void DBBrowserDB::logSQL(const QString& statement, int msgtype)
 {
     if(mainWindow)
     {
@@ -858,8 +858,10 @@ void DBBrowserDB::logSQL(QString statement, int msgtype)
         int loglimit = 300;
         if ((statement.length() > loglimit)&&(msgtype==kLogMsg_App))
         {
-            statement.truncate(32);
-            statement.append(QObject::tr("... <string too wide to log, probably contains binary data> ..."));
+            QString logst = statement;
+            logst.truncate(32);
+            logst.append(QObject::tr("... <string too wide to log, probably contains binary data> ..."));
+            mainWindow->logSql(logst, msgtype);
         }
         mainWindow->logSql(statement, msgtype);
     }
diff --git a/src/sqlitedb.h b/src/sqlitedb.h
index cbef39f1..fe15d756 100644
--- a/src/sqlitedb.h
+++ b/src/sqlitedb.h
@@ -99,11 +99,11 @@ public:
     bool updateRecord(int wrow, int wcol, const QString & wtext);
     bool browseTable( const QString & tablename, const QString& orderby = "rowid" );
 
-    bool createTable(QString name, const QList<DBBrowserField>& structure);
-    bool renameTable(QString from_table, QString to_table);
-    bool createColumn(QString table, QString field, QString type);
-    bool renameColumn(QString tablename, QString from, QString to, QString type);
-    bool dropColumn(QString tablename, QString column);
+    bool createTable(const QString& name, const QList<DBBrowserField>& structure);
+    bool renameTable(const QString& from_table, const QString& to_table);
+    bool createColumn(const QString& table, const QString& field, const QString& type);
+    bool renameColumn(const QString& tablename, const QString& from, const QString& to, const QString& type);
+    bool dropColumn(const QString& tablename, const QString& column);
 
     QStringList getTableFields(const QString & tablename);
     QStringList getTableTypes(const QString & tablename);
@@ -116,7 +116,7 @@ public:
     bool isOpen();
     void setDirty(bool dirtyval);
     bool getDirty();
-    void logSQL(QString statement, int msgtype);
+    void logSQL(const QString& statement, int msgtype);
     void setEncoding( int encoding );
     void setDefaultNewData( const QString & data );
     char * GetEncodedQStringAsPointer( const QString & input);