import a datatable (grid) by using the schema:table:column as keys.
        e.g. Sample input ( via cls_database.py -> test.csv)
        TERM,GENDER,ID,tot1,tot2
        5320,M,78,18,66
        1310,M,78,10,12
        
        Loads the following:

def import_datatable(self, l_datatable, schema='datatable', col_key=0):
        """
        import a datatable (grid) by using the schema:table:column as keys.
        e.g. Sample input ( via cls_database.py -> test.csv)
        TERM,GENDER,ID,tot1,tot2
        5320,M,78,18,66
        1310,M,78,10,12
        
        Loads the following:
        """
        key = ''
        hdr = l_datatable.get_header()
        schema_root_key = schema + ':' + os.path.basename(l_datatable.name) + ':'
        print(hdr)
        row_num = 0
        for row_num, row in enumerate(l_datatable.get_arr()):
            #print(row)
            for col_num, col in enumerate(row):
                #print('col_num, col = ', col_num, col)
                if col and col_num < len(hdr):
                    key = schema_root_key + row[col_key] + ':' + hdr[col_num]
                    self.connection.set(key, col)
                    #self.connection.lpush(key, col)
        print ('loaded ', str(row_num) , ' rows')