third-normal-form | 易学教程

Converting to Third Normal Form

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问题 How would you convert this table into Third Normal Form (and what are the resulting tables): 回答1: Here are the tables: Film (filmNo, fTitle, dirNo) Director(dirNo, dirName) FilmActor(filmNo, actNo, role, timeOnScreen) Actor(actNo, actName) 来源： https://stackoverflow.com/questions/37346125/converting-to-third-normal-form

Normal Form - 4th Normal Form

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问题 I have this data that I need to put into 3rd and 4th Normal Form. I understand the basics of normal form but I'm confused with 3rd and 4th normal form and I've checked online but still don't understand. I'm creating a database which is being used by my system. 回答1: A relation in 4NF is also in BCNF, 3NF and the lower NFs. From this answer: A superkey is a set of columns that uniquely identifies rows. A candidate key is a set of columns that uniquely identifies rows and that contains no

Violation of 3NF if we use an auto-incremented identity column along with a PK

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问题 As it is said in the book of Database Solutions Second Edition written by Thomas Connolly and Carolyn Begg page 180: Third normal form (3NF) A table that is already in 1NF and 2NF, and in which the values in all non-primary-key columns can be worked out from only the primary key column(s) and no other columns. I have seen many scenarios where people use an identity column though they already have a primary key column in their table. A record can also be worked out from the identity column, so

Can one have optional fields in a 3NF / BCNF database?

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问题 I have a database that I am trying to set up and I would like it to be in at least 3NF. However, some fields are not necessary in all situations, and the necessity of this field, not the value itself, depends on another. In essence, I want to keep track of jobs that are on hold for one reason or another. My main table right now includes these fields: Job No (primary Key) | Short Text | Storage Location | Coordinator I have other tables for employee list and storage locations. Now my problem

Violation of 3NF if we use an auto-incremented identity column along with a PK

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As it is said in the book of Database Solutions Second Edition written by Thomas Connolly and Carolyn Begg page 180: Third normal form (3NF) A table that is already in 1NF and 2NF, and in which the values in all non-primary-key columns can be worked out from only the primary key column(s) and no other columns. I have seen many scenarios where people use an identity column though they already have a primary key column in their table. A record can also be worked out from the identity column, so isn't it a violation of 3NF if we use an auto-incremented identity column along with a primary key in