diff --git a/src/definitions/definitions.h.in b/src/definitions/definitions.h.in
index b8d4a5936..2343c3429 100644
--- a/src/definitions/definitions.h.in
+++ b/src/definitions/definitions.h.in
@@ -68,16 +68,22 @@
 #define FILTER_WIDTH                    150
 #define FILTER_RIGHT_MARGIN             5
 
-#define APP_DB_TEST_MYSQL             "MySQLTest"
+#define APP_DB_PSQL_DRIVER            "QPSQL"
+#define APP_DB_PSQL_PORT              5432
+#define APP_DB_PSQL_FALLBACK_DB       "postgres"
+
+#define APP_DB_MYSQL_DRIVER           "QMYSQL"
+#define APP_DB_MYSQL_INIT             "db_init_mysql.sql"
+#define APP_DB_MYSQL_TEST             "MySQLTest"
 #define APP_DB_MYSQL_PORT             3306
-#define APP_DB_DRIVER_SQLITE          "QSQLITE"
-#define APP_DB_DRIVER_MYSQL           "QMYSQL"
-#define APP_DB_INIT_MYSQL             "db_init_mysql.sql"
-#define APP_DB_INIT_SQLITE            "db_init_sqlite.sql"
-#define APP_DB_INIT_SQLITE_MEMORY     "db_init_sqlite_memory.sql"
-#define APP_DB_INIT_SPLIT             "-- !\n"
-#define APP_DB_PATH                   "data/database/local"
-#define APP_DB_FILE                   "database.db"
+
+#define APP_DB_SQLITE_DRIVER          "QSQLITE"
+#define APP_DB_SQLITE_INIT            "db_init_sqlite.sql"
+#define APP_DB_SQLITE_MEMORY_INIT     "db_init_sqlite_memory.sql"
+#define APP_DB_SQLITE_PATH            "data/database/local"
+#define APP_DB_SQLITE_FILE            "database.db"
+
+#define APP_DB_COMMENT_SPLIT          "-- !\n"
 #define APP_DB_WEB_PATH               "data/database/web"
 
 #define APP_CFG_PATH        "data/config"
diff --git a/src/gui/formsettings.cpp b/src/gui/formsettings.cpp
index e7066df7c..5f9f2805d 100755
--- a/src/gui/formsettings.cpp
+++ b/src/gui/formsettings.cpp
@@ -513,15 +513,15 @@ void FormSettings::loadDataStorage() {
 
   // Load SQLite.
   m_ui->m_cmbDatabaseDriver->addItem(
-        tr("SQLite (embedded database)"), APP_DB_DRIVER_SQLITE);
+        tr("SQLite (embedded database)"), APP_DB_SQLITE_DRIVER);
 
   // Load in-memory database status.
   m_ui->m_checkSqliteUseInMemoryDatabase->setChecked(Settings::instance()->value(APP_CFG_DB, "use_in_memory_db", false).toBool());
 
-  if (QSqlDatabase::isDriverAvailable(APP_DB_DRIVER_MYSQL)) {
+  if (QSqlDatabase::isDriverAvailable(APP_DB_MYSQL_DRIVER)) {
     // Load MySQL.
     m_ui->m_cmbDatabaseDriver->addItem(
-          tr("MySQL/MariaDB (dedicated database)"), APP_DB_DRIVER_MYSQL);
+          tr("MySQL/MariaDB (dedicated database)"), APP_DB_MYSQL_DRIVER);
 
     // Setup placeholders.
     m_ui->m_txtMysqlHostname->lineEdit()->setPlaceholderText(tr("Hostname of your MySQL server"));
@@ -536,7 +536,7 @@ void FormSettings::loadDataStorage() {
 
   int index_current_backend = m_ui->m_cmbDatabaseDriver->findData(Settings::instance()->value(APP_CFG_DB,
                                                                                               "database_driver",
-                                                                                              APP_DB_DRIVER_SQLITE).toString());
+                                                                                              APP_DB_SQLITE_DRIVER).toString());
 
   if (index_current_backend >= 0) {
     m_ui->m_cmbDatabaseDriver->setCurrentIndex(index_current_backend);
@@ -553,13 +553,13 @@ void FormSettings::saveDataStorage() {
   }
 
   // Save data storage settings.
-  QString original_db_driver = Settings::instance()->value(APP_CFG_DB, "database_driver", APP_DB_DRIVER_SQLITE).toString();
+  QString original_db_driver = Settings::instance()->value(APP_CFG_DB, "database_driver", APP_DB_SQLITE_DRIVER).toString();
   QString selected_db_driver = m_ui->m_cmbDatabaseDriver->itemData(m_ui->m_cmbDatabaseDriver->currentIndex()).toString();
 
   // Save SQLite.
   Settings::instance()->setValue(APP_CFG_DB, "use_in_memory_db", new_inmemory);
 
-  if (QSqlDatabase::isDriverAvailable(APP_DB_DRIVER_MYSQL)) {
+  if (QSqlDatabase::isDriverAvailable(APP_DB_MYSQL_DRIVER)) {
     // Save MySQL.
     Settings::instance()->setValue(APP_CFG_DB, "mysql_hostname", m_ui->m_txtMysqlHostname->lineEdit()->text());
     Settings::instance()->setValue(APP_CFG_DB, "mysql_username", m_ui->m_txtMysqlUsername->lineEdit()->text());
diff --git a/src/miscellaneous/databasefactory.cpp b/src/miscellaneous/databasefactory.cpp
index a0612cdee..11a0be88a 100644
--- a/src/miscellaneous/databasefactory.cpp
+++ b/src/miscellaneous/databasefactory.cpp
@@ -52,8 +52,8 @@ DatabaseFactory *DatabaseFactory::instance() {
 
 DatabaseFactory::MySQLError DatabaseFactory::mysqlTestConnection(const QString &hostname, int port,
                                                                  const QString &username, const QString &password) {
-  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_DRIVER_MYSQL,
-                                                    APP_DB_TEST_MYSQL);
+  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_MYSQL_DRIVER,
+                                                    APP_DB_MYSQL_TEST);
 
   database.setHostName(hostname);
   database.setPort(port);
@@ -63,7 +63,7 @@ DatabaseFactory::MySQLError DatabaseFactory::mysqlTestConnection(const QString &
   if (database.open()) {
     // Connection succeeded, clean up the mess and return OK status.
     database.close();
-    removeConnection(APP_DB_TEST_MYSQL);
+    removeConnection(APP_DB_MYSQL_TEST);
     return MySQLOk;
   }
   else {
@@ -71,7 +71,7 @@ DatabaseFactory::MySQLError DatabaseFactory::mysqlTestConnection(const QString &
     // error code.
     MySQLError error_code = static_cast<MySQLError>(database.lastError().number());
 
-    removeConnection(APP_DB_TEST_MYSQL);
+    removeConnection(APP_DB_MYSQL_TEST);
     return error_code;
   }
 }
@@ -100,17 +100,17 @@ void DatabaseFactory::sqliteAssemblyDatabaseFilePath()  {
   if (Settings::instance()->type() == Settings::Portable) {
     m_sqliteDatabaseFilePath = qApp->applicationDirPath() +
                                QDir::separator() +
-                               QString(APP_DB_PATH);
+                               QString(APP_DB_SQLITE_PATH);
   }
   else {
     m_sqliteDatabaseFilePath = QDir::homePath() + QDir::separator() +
                                QString(APP_LOW_H_NAME) + QDir::separator() +
-                               QString(APP_DB_PATH);
+                               QString(APP_DB_SQLITE_PATH);
   }
 }
 
 QSqlDatabase DatabaseFactory::sqliteInitializeInMemoryDatabase() {
-  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_DRIVER_SQLITE);
+  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_SQLITE_DRIVER);
 
   database.setDatabaseName(":memory:");
 
@@ -136,16 +136,16 @@ QSqlDatabase DatabaseFactory::sqliteInitializeInMemoryDatabase() {
     if (query_db.lastError().isValid()) {
       qWarning("Error occurred. In-memory SQLite database is not initialized. Initializing now.");
 
-      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_INIT_SQLITE_MEMORY);
+      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_SQLITE_MEMORY_INIT);
 
       if (!file_init.open(QIODevice::ReadOnly | QIODevice::Text)) {
         // Database initialization file not opened. HUGE problem.
         qFatal("In-memory SQLite database initialization file '%s' from directory '%s' was not found. In-memory database is uninitialized.",
-               APP_DB_INIT_SQLITE,
+               APP_DB_SQLITE_INIT,
                qPrintable(APP_MISC_PATH));
       }
 
-      QStringList statements = QString(file_init.readAll()).split(APP_DB_INIT_SPLIT,
+      QStringList statements = QString(file_init.readAll()).split(APP_DB_COMMENT_SPLIT,
                                                                   QString::SkipEmptyParts);
       database.transaction();
 
@@ -154,7 +154,7 @@ QSqlDatabase DatabaseFactory::sqliteInitializeInMemoryDatabase() {
 
         if (query_db.lastError().isValid()) {
           qFatal("In-memory SQLite database initialization failed. Initialization script '%s' is not correct.",
-                 APP_DB_INIT_SQLITE);
+                 APP_DB_SQLITE_INIT);
         }
       }
 
@@ -200,7 +200,7 @@ QSqlDatabase DatabaseFactory::sqliteInitializeInMemoryDatabase() {
 QSqlDatabase DatabaseFactory::sqliteInitializeFileBasedDatabase(const QString &connection_name) {
   // Prepare file paths.
   QDir db_path(m_sqliteDatabaseFilePath);
-  QFile db_file(db_path.absoluteFilePath(APP_DB_FILE));
+  QFile db_file(db_path.absoluteFilePath(APP_DB_SQLITE_FILE));
 
   // Check if database directory exists.
   if (!db_path.exists()) {
@@ -216,7 +216,7 @@ QSqlDatabase DatabaseFactory::sqliteInitializeFileBasedDatabase(const QString &c
   // Folders are created. Create new QSQLDatabase object.
   QSqlDatabase database;
 
-  database = QSqlDatabase::addDatabase(APP_DB_DRIVER_SQLITE,
+  database = QSqlDatabase::addDatabase(APP_DB_SQLITE_DRIVER,
                                        connection_name);
   database.setDatabaseName(db_file.fileName());
 
@@ -242,16 +242,16 @@ QSqlDatabase DatabaseFactory::sqliteInitializeFileBasedDatabase(const QString &c
     if (query_db.lastError().isValid()) {
       qWarning("Error occurred. File-based SQLite database is not initialized. Initializing now.");
 
-      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_INIT_SQLITE);
+      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_SQLITE_INIT);
 
       if (!file_init.open(QIODevice::ReadOnly | QIODevice::Text)) {
         // Database initialization file not opened. HUGE problem.
         qFatal("SQLite database initialization file '%s' from directory '%s' was not found. File-based database is uninitialized.",
-               APP_DB_INIT_SQLITE,
+               APP_DB_SQLITE_INIT,
                qPrintable(APP_MISC_PATH));
       }
 
-      QStringList statements = QString(file_init.readAll()).split(APP_DB_INIT_SPLIT,
+      QStringList statements = QString(file_init.readAll()).split(APP_DB_COMMENT_SPLIT,
                                                                   QString::SkipEmptyParts);
       database.transaction();
 
@@ -260,7 +260,7 @@ QSqlDatabase DatabaseFactory::sqliteInitializeFileBasedDatabase(const QString &c
 
         if (query_db.lastError().isValid()) {
           qFatal("File-based SQLite database initialization failed. Initialization script '%s' is not correct.",
-                 APP_DB_INIT_SQLITE);
+                 APP_DB_SQLITE_INIT);
         }
       }
 
@@ -330,9 +330,12 @@ void DatabaseFactory::sqliteSaveMemoryDatabase() {
 }
 
 void DatabaseFactory::determineDriver() {
-  QString db_driver = Settings::instance()->value(APP_CFG_DB, "database_driver", APP_DB_DRIVER_SQLITE).toString();
+  QString db_driver = Settings::instance()->value(APP_CFG_DB,
+                                                  "database_driver",
+                                                  APP_DB_SQLITE_DRIVER).toString();
 
-  if (db_driver == APP_DB_DRIVER_MYSQL && QSqlDatabase::isDriverAvailable(APP_DB_DRIVER_MYSQL)) {
+  if (db_driver == APP_DB_MYSQL_DRIVER &&
+      QSqlDatabase::isDriverAvailable(APP_DB_SQLITE_DRIVER)) {
     // User wants to use MySQL and MySQL is actually available. Use it.
     m_activeDatabaseDriver = MYSQL;
 
@@ -377,7 +380,7 @@ QSqlDatabase DatabaseFactory::mysqlConnection(const QString &connection_name) {
     else {
       // Database connection with this name does not exist
       // yet, add it and set it up.
-      database = QSqlDatabase::addDatabase(APP_DB_DRIVER_MYSQL, connection_name);
+      database = QSqlDatabase::addDatabase(APP_DB_MYSQL_DRIVER, connection_name);
 
       database.setHostName(Settings::instance()->value(APP_CFG_DB, "mysql_hostname").toString());
       database.setPort(Settings::instance()->value(APP_CFG_DB, "mysql_port", APP_DB_MYSQL_PORT).toInt());
@@ -402,7 +405,7 @@ QSqlDatabase DatabaseFactory::mysqlConnection(const QString &connection_name) {
 
 QSqlDatabase DatabaseFactory::mysqlInitializeDatabase(const QString &connection_name) {
   // Folders are created. Create new QSQLDatabase object.
-  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_DRIVER_MYSQL,
+  QSqlDatabase database = QSqlDatabase::addDatabase(APP_DB_MYSQL_DRIVER,
                                                     connection_name);
 
   database.setHostName(Settings::instance()->value(APP_CFG_DB, "mysql_hostname").toString());
@@ -425,16 +428,16 @@ QSqlDatabase DatabaseFactory::mysqlInitializeDatabase(const QString &connection_
       // or schema version is wrong, then initialize it.
       qWarning("Error occurred. MySQL database is not initialized. Initializing now.");
 
-      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_INIT_MYSQL);
+      QFile file_init(APP_MISC_PATH + QDir::separator() + APP_DB_MYSQL_INIT);
 
       if (!file_init.open(QIODevice::ReadOnly | QIODevice::Text)) {
         // Database initialization file not opened. HUGE problem.
         qFatal("MySQL database initialization file '%s' from directory '%s' was not found. File-based database is uninitialized.",
-               APP_DB_INIT_MYSQL,
+               APP_DB_MYSQL_INIT,
                qPrintable(APP_MISC_PATH));
       }
 
-      QStringList statements = QString(file_init.readAll()).split(APP_DB_INIT_SPLIT,
+      QStringList statements = QString(file_init.readAll()).split(APP_DB_COMMENT_SPLIT,
                                                                   QString::SkipEmptyParts);
       database.transaction();
 
@@ -443,7 +446,7 @@ QSqlDatabase DatabaseFactory::mysqlInitializeDatabase(const QString &connection_
 
         if (query_db.lastError().isValid()) {
           qFatal("MySQL database initialization failed. Initialization script '%s' is not correct.",
-                 APP_DB_INIT_MYSQL);
+                 APP_DB_MYSQL_INIT);
         }
       }
 
@@ -513,10 +516,10 @@ QSqlDatabase DatabaseFactory::sqliteConnection(const QString &connection_name,
       else {
         // Database connection with this name does not exist
         // yet, add it and set it up.
-        database = QSqlDatabase::addDatabase(APP_DB_DRIVER_SQLITE, connection_name);
+        database = QSqlDatabase::addDatabase(APP_DB_SQLITE_DRIVER, connection_name);
 
         QDir db_path(m_sqliteDatabaseFilePath);
-        QFile db_file(db_path.absoluteFilePath(APP_DB_FILE));
+        QFile db_file(db_path.absoluteFilePath(APP_DB_SQLITE_FILE));
 
         // Setup database file path.
         database.setDatabaseName(db_file.fileName());
diff --git a/src/miscellaneous/databasefactory.h b/src/miscellaneous/databasefactory.h
index 5513facd3..24093d128 100644
--- a/src/miscellaneous/databasefactory.h
+++ b/src/miscellaneous/databasefactory.h
@@ -41,6 +41,7 @@ class DatabaseFactory : public QObject {
       FromSettings
     };
 
+    // Describes possible MySQL-specific errors.
     enum MySQLError {
       MySQLOk                 = 0,
       MySQLAccessDenied       = 1045,