An Extension to DREAM Model Based Dynamic Schema for Semi-structured Data
Mitsuru Nakata, Qi-Wei Ge, Teruhisa Hochin, Tatsuo Tsuji · Thammasat International Journal of Science and Technology · 2002
Although database technologies have been used widely, they still carl not be simply used to construct such complicated database like classical literature database or archaeological relics' database. This is because these kinds ofdata are semi-structured data that do not have regular structures, so that their database schema can't be defined before storing data. We have proposed DREAM model for semi-structured databases. In this model, a database consists of five elements and its operations are similar to that of set theory. And furthennore we have introduced dynamic schema showing structure of each element. Based on this model, we have realized a protofype of database management system, called DREAM DBMS, including the function of constructing shapes, called shape-function. However, shape is insufficient to describe database structures because it can't explain nested structures ofelements. In this paper, we refine the concept by introducing a new concept shape-graph