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How to properly normalize this table?

Subscriber Number Name Magazine Code Magazine Start Date End Date
101 Jones TIM Time Mar-93 Feb-99
110 Allen NEW Newsweek Feb-96 Jan-99
SCI Science Jun-94 May-00
202 Smith NEW Newsweek Feb-94 Jan-99
TIM Time May-94 Apr-01
TIM Time May-94 Apr-01

(third row with two blanks are still the data of Allen which has the subscriber number of 110) (same goes with 5th and 6th row two blanks, data is still from its preceding term Smith which has the subscriber number 202) (they were just left blank to identify them as the values from their preceding terms)

My process of normalizing:

First Normal Form (1NF): 1NF

Second Normal Form (2NF): 2NF

Third Normal Form (3NF): 3NF

I used this site for reference:
https://www.sqa.org.uk/e-learning/MDBS01CD/page_27.htm

philipxy
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Ralph Henry
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  • Please [use text, not images/links, for text--including tables & ERDs](https://meta.stackoverflow.com/q/285551/3404097). Paraphrase or quote from other text. Give just what you need & relate it to your problem. Use images only for what cannot be expressed as text or to augment text. Include a legend/key & explanation with an image. PS You don't explain why or how your "mistakes" are mistakes or what that or they have to do with a question about getting to 3NF. So why are they there? (Rhetorical.) – philipxy Jul 17 '21 at 07:08
  • Right now you are just asking for us to rewrite a textbook with a bespoke tutorial & do your (home)work. Please see [ask], hits googling 'stackexchange homework' & the voting arrow mouseover texts. Show the steps of your work following a textbook/reference with justification & ask 1 specific researched non-duplicate question re the first place you are stuck. Quote the definitions, theorems, algorithms & heuristics you are relying on. All the steps are also SO faqs. Google with & without 'site:stackoverflow.com'. – philipxy Jul 17 '21 at 07:13
  • "Research" includes following a reasonable reference. Dozens of published academic textbooks are free online. Youtube & random web sites are not reasonable resources. The link you give is not helpful. If you were in a class, what is its textbook? (While you were commenting I was removing the inappropriate "shows no research" from my prefab comment.) PS ["1NF" has many meanings.](https://stackoverflow.com/a/40640962/3404097) All involve replacing some table with parameterized structure by some table(s) with a column per parameter. So again if you are in a class you need to give its definitions. – philipxy Jul 17 '21 at 07:21
  • Are you normalizing that relation value, or a relation variable that can hold that value? – philipxy Jul 17 '21 at 07:24
  • @philipxy normalizing the values (well it can also involve with the relations) – Ralph Henry Jul 17 '21 at 07:25
  • Please clarify via edits, not comments. But your comment is not clear. PS Your link says about its process "This data is not simply the data on the report but a representative sample." (But it is not a useful presentation of normalization.) Good luck. – philipxy Jul 17 '21 at 07:35

1 Answers1

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I suspect a spreadsheet is not the best way to normalize data.

The first thing you do is determine the entities or objects that make up your database.

In your example, I see Subscriber, Magazine, and Subscription as entities.

The next thing you do is determine the relationship between the entities.

  • A Subscriber can subscribe to one or more Magazines.
  • A Magazine runs for a Subscription period.
  • A Subscription is a relationship between a Subscriber and a Magazine.

I'm going to leave the rest to you. There are plenty of resources available that show you how to normalize data, including this Wikipedia article.

Gilbert Le Blanc
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