AJ-460: addColumn's colName cannot be empty.

Author: chengyitian

src/com/xxdb/data/BasicTable.java

@@ -381,6 +381,9 @@ public void addColumn(String colName, Vector col) {
 		if (Objects.isNull(colName) || Objects.isNull(col))
 			throw new RuntimeException("The param 'colName' or 'col' in table cannot be null.");
 
+		if (colName.isEmpty())
+			throw new RuntimeException("The param 'colName' cannot be empty.");
+
 		if (colNames.contains(colName))
 			throw new RuntimeException("The table already contains column '" + colName + "'.");