Most of the XML query processing strategies are based on some numbering schemes. Nodes on the XML tree will be assigned a unique code by the numbering scheme, and ancestor-descendant relationship could be directly told through the codes. The most famous numbering scheme is Region Based Numbering Scheme. However, XML data will be updated. Once the data is updated, the region code should be adjusted to keep the indexing and query processing techniques working. Unfortunately, few studies have been reported on the issue of the numbering scheme. This paper focuses on this issue, proposing a series of space preserving and updating algorithms. Extensive experiments are conducted to test the effectiveness of the algorithms.