R. Krishnamurthy, W. Litwin, and W. Kent. Language features for interoperability of heterogeneous databases with schematic discrepancies. In Proc. ACM SIGMOD, pages 40--9, Denver, CO, May 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....without producing erroneous or unexpected results. ffl MSL can integrate sources whose object structures we do not fully know (see Section 2) ffl MSL can manipulate both the values and the descriptive semantic labels in the same fashion, getting around problems such as schematic discrepancies [KLK91] see Section 2) Further3 more, MSL can also manipulate object id s in the same fashion as values, providing object identification on top of value oriented sources (see Section 4.5) ffl MSL provides a flexible technique (based on object identity) for grouping of source objects that relate to ....

....integration systems, we discuss our motivation behind the design of OEM and MSL, and we describe our ongoing work on MedMaker. It is widely accepted that the relational data model and the corresponding view definition languages are insufficient to provide integration, even of relational databases [KLK91] Thus, many projects have adopted (or defined) OO models to facilitate integration (some examples are [C 94, A 91, LM93] A difference between OEM and conventional OO models is that OEM is much simpler and does not have a strong type system. OEM supports only object nesting and ....

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R. Krishnamurthy, W. Litwin, and W. Kent. Language features for interoperability of heterogeneous databases with schematic discrepancies. In Proc. ACM SIGMOD, pages 40--9, Denver, CO, May 1991.

.... MSL s handling of semantic object ids is based on a particular use of Skolem functions as first introduced in object oriented systems in [Mai86] and refined in [KKS92, CKW93] Automatic creation and manipulation of object id s based on Skolem functors are considered in depth in [HY90] LSS93, KLK91] propose logics and languages with higher order syntax and firstorder semantics for schema integration and evolution and also demonstrates the need for higher order views. MSL achieves the same effects with the use of label variables. Finally, though MSL can be reduced to a variant of Datalog ....

R. Krishnamurthy, W. Litwin, and W. Kent. Language features for interoperability of heterogeneous databases with schematic discrepancies. In Proc. ACM SIGMOD, pages 40--9, Denver, CO, May 1991.

....data is also considered in [C 94, FK93, Q , PGMU, ACM93, PDS95] We believe that approaches based on the relational model (and corresponding view definition languages) are not applicable here. Indeed, one may argue that they are insufficient even for relational database integration [KLK91] Object oriented database systems do provide more flexibility. However, their strict type system sometimes is a handicap [C 94, BDH 95] Also, primitives for data integration found in these systems are still quite limited, with some exceptions like work on views in the context of OQL ....

....in lower level sources (that can themselves be mediators) LSS93] proposes a logic with higher order syntax and first order semantics for schema integration and evolution and also demonstrates the need for higher order views. MSL achieves the same effects with the use of label variables. KLK91] achieves the same objective by assuming special virtual relations that contain the metadata information of the repositories relation. Finally, though MSL can be reduced to a variant of datalog [Ull89] query execution against mediators cannot be achieved by a simple modification of datalog ....

R. Krishnamurthy, W. Litwin, and W. Kent. Language features for interoperability of heterogeneous databases with schematic discrepancies. In Proc. ACM SIGMOD, pages 40--9, Denver, CO, May 1991.

....without producing erroneous or unexpected results. ffl MSL can integrate sources for which we do not fully know their object structures. ffl MSL can manipulate both the values and the descriptive semantic labels in the same fashion, getting around problems such as schematic discrepancies [KLK91] The above capabilities are packaged in a high level declarative language that combines power with simplicity and conciseness, thus allowing the client of an heterogeneous system to easily define an integrated view. In the next section we present an extended example that illustrates the MSL ....

....systems, we discuss our motivation behind the design of OEM and MSL, and we describe our ongoing work on MedMaker. It is widely accepted that the relational data model and the corresponding view definition languages are insufficient to provide integration, even of relational databases [KLK91] Thus, many projects have adopted (or defined) OO models to facilitate integration (some examples are [C 94, A 91] We described in Sections 1 and 2 the OEM features that make it suitable for integration of heterogeneous information systems. Another difference between OEM and ....

[Article contains additional citation context not shown here]

R. Krishnamurthy, W. Litwin, and W. Kent. Language features for interoperability of heterogeneous databases with schematic discrepancies. In Proc. ACM SIGMOD, pages 40--9, Denver, CO, May 1991.

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