diff --git a/GeoModelIO/GeoModelDBManager/GeoModelDBManager/GMDBManager.h b/GeoModelIO/GeoModelDBManager/GeoModelDBManager/GMDBManager.h
index 356b280771ea20a6f109125a8165170954138b11..8f8e72e15e5b1fafebb7d43d6aaa0b30fe5c8f7f 100644
--- a/GeoModelIO/GeoModelDBManager/GeoModelDBManager/GMDBManager.h
+++ b/GeoModelIO/GeoModelDBManager/GeoModelDBManager/GMDBManager.h
@@ -358,68 +358,86 @@ class GMDBManager {
 
 
    private:
-    /**
-     * @brief Create all the default DB tables.
-     */
-    bool createTables();
+       /* NOTE: 'sqlite3_column_type' return codes:
+        - 1 INT
+        - 2 FLOAT
+        - 3 TEXT
+        - 4 BLOB
+        - 5 NULL
+       */
+       enum SQLiteColumnTypes : int
+       {
+           INT_TYPE = 1,
+           FLOAT_TYPE = 2,
+           TEXT_TYPE = 3,
+           BLOB_TYPE = 4,
+           NULL_TYPE = 5
+       };
 
-    /**
-     * @brief Create a custom DB table to store a list of published nodes.
-     * @param tableName The table's name.
-     * @param keyType The type of the 'key' that identifies the linked node.
-     */
-    bool createTableCustomPublishedNodes(const std::string tableName,
-                                         const std::string nodeType,
-                                         const std::type_info *keyType);
+       /**
+        * @brief Create all the default DB tables.
+        */
+       bool createTables();
 
-    void addDBversion(std::string version);
+       /**
+        * @brief Create a custom DB table to store a list of published nodes.
+        * @param tableName The table's name.
+        * @param keyType The type of the 'key' that identifies the linked node.
+        */
+       bool createTableCustomPublishedNodes(const std::string tableName,
+                                            const std::string nodeType,
+                                            const std::type_info *keyType);
 
-    //  void loadTestData(); // for debug only
+       void addDBversion(std::string version);
 
-    std::string getTableNameFromTableId(unsigned int tabId);
+       //  void loadTestData(); // for debug only
 
-    void storeNodeType(std::string nodeType, std::string tableName);
+       std::string getTableNameFromTableId(unsigned int tabId);
 
-    std::string getTableNameFromNodeType(const std::string &nodeType);
+       void storeNodeType(std::string nodeType, std::string tableName);
 
-    void storeTableColumnNames(std::vector<std::string> input);
+       std::string getTableNameFromNodeType(const std::string &nodeType);
 
-    std::vector<std::string> getTableColumnNames(const std::string &tableName);
-    bool hasTableBeenCreatedInDB(const std::string_view tableName);
+       std::vector<std::string> getTableColumnNames(const std::string &tableName);
+       bool hasTableBeenCreatedInDB(const std::string_view tableName);
+       void storeTableColumnNames(std::vector<std::string> input);
 
-    int getTableColIndex(const std::string &tableName,
-                         const std::string &colName);
+       bool storeRootVolume(const unsigned &id, const std::string_view nodeType);
+       int getTableColIndex(const std::string &tableName,
+                            const std::string &colName);
 
-    bool storeRootVolume(const unsigned &id, const std::string_view nodeType);
+       bool storeRootVolume(const unsigned int &id, const std::string &nodeType);
 
-    std::string m_dbpath;
+       std::string m_dbpath;
 
-    bool m_debug;
+       bool m_debug;
 
-    // verbosity level
-    int m_verbose;
+       // verbosity level
+       int m_verbose;
 
-    /// stores the column names for each table
-    std::unordered_map<std::string, std::vector<std::string>> m_tableNames;
+       /// stores the column names for each table
+       std::unordered_map<std::string, std::vector<std::string>> m_tableNames;
 
-    std::unordered_map<std::string, std::string> m_childType_tableName;
+       std::unordered_map<std::string, std::string> m_childType_tableName;
 
-    /// cache for the list of tables in the DB
-    // std::vector<std::string> m_cache_tables;
-    std::set<std::string> m_cache_tables;
+       /// cache for the list of tables in the DB
+       // std::vector<std::string> m_cache_tables;
+       std::set<std::string> m_cache_tables;
 
-    std::unordered_map<unsigned int, std::string>
-        m_cache_tableId_tableName;  /// cache for tableID-->tableName
-    std::unordered_map<unsigned int, std::string>
-        m_cache_tableId_nodeType;  /// cache for tableID-->nodeType
-    std::unordered_map<std::string, std::string>
-        m_cache_nodeType_tableName;  /// cache for nodeType-->tableName
-    std::unordered_map<std::string, unsigned int>
-        m_cache_nodeType_tableID;  /// cache for nodeType-->tableID
+       std::unordered_map<unsigned int, std::string>
+           m_cache_tableId_tableName; /// cache for tableID-->tableName
+       std::unordered_map<unsigned int, std::string>
+           m_cache_tableId_nodeType; /// cache for tableID-->nodeType
+       std::unordered_map<std::string, std::string>
+           m_cache_nodeType_tableName; /// cache for nodeType-->tableName
+       std::unordered_map<std::string, unsigned int>
+           m_cache_nodeType_tableID; /// cache for nodeType-->tableID
 
    protected:
     class Imp;
     Imp *m_d;
+
+
 };
 
 #endif  // GMDBManager_H
diff --git a/GeoModelIO/GeoModelDBManager/src/GMDBManager.cpp b/GeoModelIO/GeoModelDBManager/src/GMDBManager.cpp
index 7b7f9b825c5441f726d41651417888aa02295d44..c037426df77ac6763a42540ca334d63206dbdd4b 100644
--- a/GeoModelIO/GeoModelDBManager/src/GMDBManager.cpp
+++ b/GeoModelIO/GeoModelDBManager/src/GMDBManager.cpp
@@ -328,13 +328,6 @@ DBRowsList GMDBManager::getTableRecords_VecVecData(
                 for (int i = 0; i < ctotal;
                      i++)
                 {
-                    /* NOTE: 'sqlite3_column_type' return codes:
-                       - 1 INT
-                       - 2 FLOAT
-                       - 3 TEXT
-                       - 4 BLOB
-                       - 5 NULL
-                    */
                     int datacode = sqlite3_column_type(stmt, i);
                     // debug msg
                     // if (0==nRows) std::cout << "table: " << tableName << ", col " << i << "/" << ctotal << " -- typecode: " << datacode << std::endl;
@@ -344,21 +337,21 @@ DBRowsList GMDBManager::getTableRecords_VecVecData(
                     std::string valS;
 
                     // ** INT **
-                    if (1 == datacode)
+                    if (SQLiteColumnTypes::INT_TYPE == datacode)
                     {
                         valI = sqlite3_column_int(stmt, i);
                         // if (0==nRows) std::cout << "valI: " << valI << std::endl;// debug msg
                         nodeParams.push_back(valI);
                     }
                     // ** FLOAT **
-                    else if (2 == datacode)
+                    else if (SQLiteColumnTypes::FLOAT_TYPE == datacode)
                     {
                         valD = sqlite3_column_double(stmt, i);
                         // if (0==nRows) std::cout << "valD: " << valD << std::endl;// debug msg
                         nodeParams.push_back(valD);
                     }
                     // ** TEXT **
-                    else if (3 == datacode)
+                    else if (SQLiteColumnTypes::TEXT_TYPE == datacode)
                     {
                         const char *cc = (char *)sqlite3_column_text(stmt, i);
                         if (cc == NULL)
@@ -372,18 +365,18 @@ DBRowsList GMDBManager::getTableRecords_VecVecData(
                         nodeParams.push_back(valS);
                     }
                     // ** BLOB **
-                    else if (4 == datacode)
+                    else if (SQLiteColumnTypes::BLOB_TYPE == datacode)
                     {
                         THROW_EXCEPTION("ERROR!!! The 'BLOB' data format is not supported yet!!");
                     }
                     // ** NULL **
-                    else if (5 == datacode)
+                    else if (SQLiteColumnTypes::NULL_TYPE == datacode)
                     {
-                        THROW_EXCEPTION("WARNING! 'NULL' format detected. Check that!");
+                        THROW_EXCEPTION("ERROR!!! 'NULL' format detected. Check that!");
                     }
                     else
                     {
-                        THROW_EXCEPTION("ERROR!!! You should NOT get here!! Unsupport SQLite data typecode: " << datacode << " -- Check this!!");
+                        THROW_EXCEPTION("ERROR!!! You should NOT get here!! Unsupported SQLite data typecode: " << datacode << " -- Check this!!");
                     }
                 }
                 records.push_back(nodeParams);
@@ -431,7 +424,8 @@ DBRowEntry GMDBManager::getTableRecords_VecData(
     {
         // Count the Number of Columns in the Table
         int ctotal = sqlite3_column_count(stmt);
-        // for this case, we should have only one column
+        // Note: for this case, we should have only one column of data;
+        // so, we throw an error if we get more than two columns in total
         if (ctotal > 2)
         {
             THROW_EXCEPTION("ERROR! Table '" << tableName << "' is supposed to have two columns only, one for the ID and one for actual data; but it has '"
@@ -443,22 +437,11 @@ DBRowEntry GMDBManager::getTableRecords_VecData(
             res = sqlite3_step(stmt); // Execute SQL Statement.
             if (res == SQLITE_ROW)
             {
-                // stores the value contained in a single row
-                // std::variant<int, long, float, double, std::string> rowValue;
-
-                // we are only interested in returning the 'data' column, that is column '1'
-                // (column '0' contains the ID)
+                // NOTE: 
+                // we are only interested in returning 
+                // the 'data' column, that is column '1'
+                // (while column '0' contains the ID)
                 int colData = 1;
-                // for (int i = 0; i < ctotal;
-                    //  i++) // Loop times the number of columns in the table
-                // {
-                    /* NOTE: 'sqlite3_column_type' return codes:
-                       - 1 INT
-                       - 2 FLOAT
-                       - 3 TEXT
-                       - 4 BLOB
-                       - 5 NULL
-                    */
                     int datacode = sqlite3_column_type(stmt, 1);
                     // debug msg
                     // std::cout << "table: " << tableName << ", col " << colData << "/" << ctotal << " -- typecode: " << datacode << std::endl;
@@ -466,17 +449,17 @@ DBRowEntry GMDBManager::getTableRecords_VecData(
                     int valI{0};
                     double valD{0.};
                     std::string valS;
-                    if (1 == datacode)
+                    if (SQLiteColumnTypes::INT_TYPE == datacode)
                     {
                         valI = sqlite3_column_int(stmt, colData);
                         records.push_back(valI);
                     }
-                    else if (2 == datacode)
+                    else if (SQLiteColumnTypes::FLOAT_TYPE == datacode)
                     {
                         valD = sqlite3_column_double(stmt, colData);
                         records.push_back(valD);
                     }
-                    else if (3 == datacode)
+                    else if (SQLiteColumnTypes::TEXT_TYPE == datacode)
                     {
                         const char *cc = (char *)sqlite3_column_text(stmt, colData);
                         if (cc == NULL)
@@ -489,20 +472,18 @@ DBRowEntry GMDBManager::getTableRecords_VecData(
                         }
                         records.push_back(valS);
                     }
-                    else if (4 == datacode)
+                    else if (SQLiteColumnTypes::BLOB_TYPE == datacode)
                     {
                         THROW_EXCEPTION("ERROR!!! The 'BLOB' data format is not supported yet!!");
                     }
-                    else if (5 == datacode)
+                    else if (SQLiteColumnTypes::NULL_TYPE == datacode)
                     {
-                        std::cout << "WARNING! 'NULL' format detected. Check that!" << std::endl;
+                        std::cout << "ERROR!!! 'NULL' format detected. Check that!" << std::endl;
                     }
                     else
                     {
-                        THROW_EXCEPTION("ERROR!!! You should NOT get here!! Unsupport SQLite data typecode: " << datacode << " -- Check this!!");
+                        THROW_EXCEPTION("ERROR!!! You should NOT get here!! Unsupported SQLite data typecode: " << datacode << " -- Check this!!");
                     }
-                // }
-                // records.push_back(rowValue);
             }
 
             if (res == SQLITE_DONE || res == SQLITE_ERROR)