Schema Mappings and Data Examples: An Interplay between Syntax and Semantics

Quasi-inverses of schema mappings

Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '07 ◽

10.1145/1265530.1265548 ◽

2007 ◽

Cited By ~ 16

Author(s):

Ronald Fagin ◽

Phokion G. Kolaitis ◽

Lucian Popa ◽

Wang-Chiew Tan

Keyword(s):

Schema Mappings

Download Full-text

Validation of schema mappings with nested queries

Computer Science and Information Systems ◽

10.2298/csis120713042r ◽

2013 ◽

Vol 10 (1) ◽

pp. 79-104

Author(s):

Guillem Rull ◽

Carles Farré ◽

Ernest Teniente ◽

Toni Urpí

Keyword(s):

Integrity Constraints ◽

Automatic Process ◽

Document Type ◽

Relational Schemas ◽

Schema Mappings ◽

Nested Data ◽

Nested Queries ◽

The Given ◽

Human Designer ◽

The Web

With the emergence of the Web and the wide use of XML for representing data, the ability to map not only flat relational but also nested data has become crucial. The design of schema mappings is a semi-automatic process. A human designer is needed to guide the process, choose among mapping candidates, and successively refine the mapping. The designer needs a way to figure out whether the mapping is what was intended. Our approach to mapping validation allows the designer to check whether the mapping satisfies certain desirable properties. In this paper, we focus on the validation of mappings between nested relational schemas, in which the mapping assertions are either inclusions or equalities of nested queries. We focus on the nested relational setting since most XML?s Document Type Definitions (DTDs) can be represented in this model. We perform the validation by reasoning on the schemas and mapping definition. We take into account the integrity constraints defined on both the source and target schema. We consider constraints and mapping?s queries which may contain arithmetic comparisons and negations. This class of mapping scenarios is significantly more expressive than the ones addressed by previous work on nested relational mapping validation. We encode the given mapping scenario into a single flat database schema, so we can take advantage of our previous work on validating flat relational mappings, and reformulate each desirable property check as a query satisfiability problem.

Download Full-text