Tham khảo Dạng chuẩn 1

  1. ↑ Elmasri, Ramez; Navathe, Shamkant B. (tháng 7 năm 2003). Fundamentals of Database Systems, Fourth Edition. Pearson. tr. 315. ISBN 0321204484. It states that the domain of an attribute must include only atomic (simple, indivisible) values and that the value of any attribute in a tuple must be a single value from the domain of that attribute. 
  2. ↑ E. F. Codd (tháng 10 năm 1972), Further normalization of the database relational model, Courant Institute: Prentice-Hall, ISBN 013196741X, A relation is in first normal form if it has the property that none of its domains has elements which are themselves sets. 
  3. ↑ Watt, Adrienne; Eng, Nelson (2014). Database Design - 2nd Edition. Victoria, B.C: BCcampus. 
  4. ↑ studytonight.com
  5. ↑ stackoverflow.com
  6. ↑ In the "real" world, that would not be a good assumption.
  7. ↑ Codd, E. F. The Relational Model for Database Management Version 2 (Addison-Wesley, 1990).
  8. ↑ Codd, E. F. The Relational Model for Database Management Version 2 (Addison-Wesley, 1990), p. 6.
  9. ↑ Darwen, Hugh. "Relation-Valued Attributes; or, Will the Real First Normal Form Please Stand Up?", in C. J. Date and Hugh Darwen, Relational Database Writings 1989-1991 (Addison-Wesley, 1992).
  10. ↑ "[F]or many years," writes Date, "I was as confused as anyone else. What's worse, I did my best (worst?) to spread that confusion through my writings, seminars, and other presentations." Date, C. J. ["What First Normal Form Really Means"] in Date on Database: Writings 2000-2006 (Springer-Verlag, 2006), p. 108
  11. ↑ Date, C. J. ["What First Normal Form Really Means"] p. 112.
  12. ↑ C.J. Date (ngày 6 tháng 11 năm 2015). SQL and Relational Theory: How to Write Accurate SQL Code. "O'Reilly Media, Inc.". tr. 50–. ISBN 978-1-4919-4115-7. Truy cập ngày 31 tháng 10 năm 2018. 
  13. ↑ Date, C. J. ["What First Normal Form Really Means"] pp. 127–128.
  14. ↑ "Codd first defined the relational model in 1969 and didn't introduce nulls until 1979" Date, C. J. SQL and Relational Theory (O'Reilly, 2009), Appendix A.2.
  15. ↑ The third of Codd's 12 rules states that "Null values... [must be] supported in a fully relational DBMS for representing missing information and inapplicable information in a systematic way, independent of data type." Codd, E. F. "Is Your DBMS Really Relational?" Computerworld, ngày 14 tháng 10 năm 1985.
  16. ↑ Date, C. J. ["What First Normal Form Really Means"] pp. 121–126.

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