On the Boyce - Codd normal form for relation scheme.
نویسندگان
چکیده
منابع مشابه
Finding Faithful Boyce-Codd Normal Form Decompositions
It is well known that faithful (i.e. dependency preserving) decompositions of relational database schemas into Boyce-Codd Normal Form (BCNF) do not always exist, depending on the set of functional dependencies given, and that the corresponding decision problem is NPhard. The only algorithm to guarantee both faithfulness and BCNF (if possible) proposed so far in [Os79] is a brute-force approach ...
متن کاملThe Boyce-Codd-Heath Normal Form for SQL
In the relational model of data the Boyce-Codd-Heath normal form, commonly just known as Boyce-Codd normal form, guarantees the elimination of data redundancy in terms of functional dependencies. For efficient means of data processing the industry standard SQL permits partial data and duplicate rows of data to occur in database systems. Consequently, the combined class of uniqueness constraints...
متن کاملCharacterizations for Functional Dependency and Boyce-CODD Normal Form Families
A functional dependency (fd) family was recently defined [20] as the set of all instances satisfying some set of functional dependencies. A Royce-Codd normal form, abbreviated RCNF. family is defined here as an fd-family specified by some RCNF set of functi!)nal dependem& . The purpose of this paper is to present set-theoretic/algebraic characterizations relating to both types of families. Two ...
متن کاملSome Problems Related to Keys and the Boyce-Codd Normal Form
The aim of this paper is to investigate the connections between minimal keys and antikeys for special Sperner-systems by hypergraphs. The BoyceCodd normal form and some related problems are also studied in this paper.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Computer Science and Cybernetics
سال: 2013
ISSN: 1813-9663,1813-9663
DOI: 10.15625/1813-9663/16/1/2846