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A Guide to the SQL standard, 4th ed., Addison Wesley, USA 1997, ISBN 978-0-201-96426-4; What Not How: The Business Rules Approach to Application Development, 2000, ISBN 0-201-70850-7; The Database Relational Model: A Retrospective Review and Analysis, 2001, ISBN 0-201-61294-1; Temporal Data & the Relational Model, 2003, ISBN 1-55860-855-9
National standard format is yyyy-mm-dd. [161] dd.mm.yyyy format is used in some places where it is required by EU regulations, for example for best-before dates on food [162] and on driver's licenses. d/m format is used casually, when the year is obvious from the context, and for date ranges, e.g. 28-31/8 for 28–31 August.
In SQL (Structured Query Language), the term cardinality refers to the uniqueness of data values contained in a particular column (attribute) of a database table. The lower the cardinality, the more duplicated elements in a column. Thus, a column with the lowest possible cardinality would have the same value for every row.
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Additionally, days from some recent years (currently: 2003–2005) have an article with a title in the format "<Month> <day number>, <year>", e.g. February 27, 2003 – these articles on a specific day of a specific year can be reached from the "<Month> <day number>" articles via the {{This date in recent years}} template. An example of this ...
Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form:
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Let's set an example convention saying a book up to 350 pages is considered "slim" and a book over 350 pages is considered "thick". This convention is technically a constraint but it is neither a domain constraint nor a key constraint; therefore we cannot rely on domain constraints and key constraints to keep the data integrity.