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In contrast, the 5NF design excludes the possibility of such inconsistencies. A table T is in fifth normal form (5NF) or projection-join normal form (PJ/NF) if it cannot have a lossless decomposition into any number of smaller tables. The case where all the smaller tables after the decomposition have the same candidate key as the table T is ...
Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by British computer scientist Edgar F. Codd as part of his relational model .
A database of biomedical and life sciences literature with access to full-text research articles and citations. [56] Includes text-mining tools and links to external molecular and medical data sets. A partner in PMC International. [57] Free EMBL-EBI [58] FSTA – Food Science and Technology Abstracts: Food science, food technology, nutrition
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A full-text database or a complete-text database is a database that contains the complete text of books, dissertations, journals, magazines, newspapers or other kinds of textual documents. They differ from bibliographic databases (which contain only bibliographical metadata , including abstracts in some cases) and non-bibliographic databases ...
A table is in EKNF if and only if all its elementary functional dependencies begin at whole keys or end at elementary key attributes. For every full non-trivial functional dependency of the form X→Y, either X is a key or Y is (a part of) an elementary key.
Essential tuple normal form (ETNF) is a normal form used in database normalization.It lies strictly between fourth normal form (4NF) and fifth normal form (5NF). As per the original paper, ETNF, although strictly weaker than 5NF, is exactly as effective as 5NF in eliminating redundancy of tuples.
Domain-key normal form (DK/NF or DKNF) is a normal form used in database normalization which requires that the database contains no constraints other than domain constraints and key constraints. A domain constraint specifies the permissible values for a given attribute, while a key constraint specifies the attributes that uniquely identify a ...