Traditional databases are for structured, record oriented data.
As the size and the complexity of data on the web grow, such documents on the web are increasingly being generated automatically from databases as opposed being generated manually. Hence, the document data on the web has some sort of regularity in structure. This leads to research on semistructured data, referring to data with some underlying structure not as strict as that of highly structured data models of traditional databases, such as the relational model. XML is a new standard for data representation on the web and for exchange of semistructured and structured data among computer systems. Then, I will discuss some research problems in databases involving semistructured data.