A Semantics-based Approach to Design of Query Languages for Partial Information

Most of work on partial information in databases asks which operations of standard languages, like relational algebra, can still be performed correctly in the presence of nulls. In this paper a di erent point of view is advocated. We believe that the semantics of partiality must be clearly understood and it should give us new design principles for languages for databases with partial information. There are di erent sources of partial information, such as missing information and con icts that occur when di erent databases are merged. In this paper, we develop a common semantic framework for them which can be applied in a context more general than the at relational model. This ordered semantics, which is based on ideas used in the semantics of programming languages, cleanly intergrates all kinds of partial information and serves as a tool to establish connections between them. Analyzing properties of semantic domains of types suitable for representing partial information, we come up with...

• Type: Conference
• Year: 1995
• Where: SDB
• Authors: Leonid Libkin
• Keywords: Database, Partial Information, SDB 1995, Semantics