Applications of Logic Databases by Oris Friesen, Gilles Gauthier-Villars (auth.), Raghu

By Oris Friesen, Gilles Gauthier-Villars (auth.), Raghu Ramakrishnan (eds.)

The premise in the back of constructing robust declarative database languages is compelling: by way of allowing clients to specify their queries (and their integrity constraints) in a transparent, non-operational approach, they make the user's job more straightforward, and supply the database method with extra possibilities for optimization. Relational database platforms supply a amazing facts that this premise is certainly legitimate. the most well-liked relational question language, SQL, relies upon relational algebra and calculus, i.e., a small fragment of first-order good judgment, and the convenience of writing queries in SQL (in comparability to extra navigational languages) has been an incredible consider the industrial luck of relational databases. it's recognized that SQL has a few vital barriers, despite its good fortune and recognition. particularly, the question language is non-recursive, and help for integrity constraints is proscribed. certainly, spotting those difficulties, the most recent regular, SQL-92, offers elevated help for integrity constraints, and it's expected that the successor to the SQL-92 normal, known as SQL3, RECURSIVE UNION operation [1]. good judgment database structures have will contain a targeting those extensions to the relational database paradigm, and a few platforms (e.g., Bull's DEL prototype) have even included object-oriented positive factors (another extension more likely to look in SQL3).

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By Oris Friesen, Gilles Gauthier-Villars (auth.), Raghu Ramakrishnan (eds.)

The premise in the back of constructing robust declarative database languages is compelling: by way of allowing clients to specify their queries (and their integrity constraints) in a transparent, non-operational approach, they make the user's job more straightforward, and supply the database method with extra possibilities for optimization. Relational database platforms supply a amazing facts that this premise is certainly legitimate. the most well-liked relational question language, SQL, relies upon relational algebra and calculus, i.e., a small fragment of first-order good judgment, and the convenience of writing queries in SQL (in comparability to extra navigational languages) has been an incredible consider the industrial luck of relational databases. it's recognized that SQL has a few vital barriers, despite its good fortune and recognition. particularly, the question language is non-recursive, and help for integrity constraints is proscribed. certainly, spotting those difficulties, the most recent regular, SQL-92, offers elevated help for integrity constraints, and it's expected that the successor to the SQL-92 normal, known as SQL3, RECURSIVE UNION operation [1]. good judgment database structures have will contain a targeting those extensions to the relational database paradigm, and a few platforms (e.g., Bull's DEL prototype) have even included object-oriented positive factors (another extension more likely to look in SQL3).

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2] Cattell, R. G. , The Object Database Standard: ODMG-93, Morgan Kaufmann, 1994. [3] Krishnamurthy, R. and T. Imielinski, "Research Directions in Knowledge Discovery," SIGMOD Record, September 1991, pp. 76-78. , "Urban School Improvement Project Proposal," University of Illinois, May 8, 1992. , "Data Dredging," Data Engineering, Dec. 1990, pp. 58-63. , P. Bayer, A. Lefebvre and V. Kuechenhoff, "EKS, A Short Overview," AAAI-90 Workshop on Knowledge Management Systems. July 1990. edu ABSTRACT This chapter discusses an extended deductive database prototype system, Q-Data, developed by Bellcore to improve data quality through data validation and cleanup.

If so, then these other students have probably been "hanging around," or have had some "contact" with the problem_students identified above. " Perhaps (we hypothesize) such "contact" can be defined by a relationship that focuses on class periods that are missed by some set of students. We know there is an attendance record for each class period in which every student has been enrolled for every day of instruction. We first need to identify students (and the associated date) who have missed at least one class period with an unexcused absence (but not the entire day).

This requires the use of soft match on the EntName column. Uniqueness constraints Uniqueness constraints, where the value of attributes in each row of a given table must be unique, are enforced by most DBMSs. Defining a column as a key for a table implies that all the values in that column should be unique. Examples of uniqueness constraints for this application include: • 'EntCode' in the 'Enterprises' table, and • the set of attributes (TeINumber, Type, Number) in the 'Names' table. Referential Integrity Constraints Referential integrity constraints specify that values of an attribute in one table must occur in another table (possibly being managed by a different DBMS).

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