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> Composite Indexes Vs Composite Primary Keys, Wiki Talk    
 
   
ButtonMoon
post Oct 11 2013, 05:38 AM
Post#1


Utterly Banned
Posts: 136
Joined: 11-January 12



I can't reply in this thread, it appears to be locked, so I'm posting here.
e: http://www.UtterAccess.com/wiki/index.php?...te_Primary_Keys
The weasel words of the first sentence aren't "debatable" content, they are just wrong content. Composite keys are never a violation of 1NF and except in this one case I haven't heard anyone claim that they are.
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datAdrenaline
post Sep 7 2014, 09:35 PM
Post#2


UtterAccess Editor
Posts: 18,001
Joined: 4-December 03
From: Northern Virginia, USA


Some terms to note ...
Key: a field (attribute) or group of fields (attributes). Nothing more, nothing less.
Natural Key: a key that is composed of attributes that describe the entity (no "system" fields, like an autonumber field).
Surrogate Key: a key that has at least one "system" field, like an autonumber field.
Composite Key: a key with multiple fields.
Candidate Key: a key the uniquely identifies a row of data.
Primary Key: in the context of a Table, it is the candidate key defined as the "primary" one. In the context of a relationship, the candidate key used on the "primary" table (aka: parent table) that is referenced by the foreign table. The key of the foreign table (aka: child table) of the relationship is called the Foreign Key.
----
- All tables should have a Primary Key. Many DBMS do not require a primary key to design/create a base table.
- ACE/Jet is fine database management system, So is SQL Server, Oracle, and many others -- they each have some characteristics that allow a programmer to blatantly ignore normalization rules -- heck its not that hard to design a non-normalized database in ANY dbms. Remember, the relational data model is a way to design schema, normalization guidelines help you adhere to the relational data model. A database designed to 3NF (3rd normal form) is a typical goal.
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Posts in this topic
- ButtonMoon   Composite Indexes Vs Composite Primary Keys, Wiki Talk   Oct 11 2013, 05:38 AM
- - genoma111   OT: I think posts in that thread are moderated mea...   Oct 11 2013, 05:42 AM
- - ButtonMoon   I can't even comment. When I click reply I get...   Oct 11 2013, 05:52 AM
- - argeedblu   Someone will be taking a look at what's going ...   Oct 11 2013, 06:48 AM
- - CyberCow   We're looking into it and have verified the pr...   Oct 11 2013, 08:53 AM
- - datAdrenaline   "The weasel words of the first sentence aren...   Oct 12 2013, 11:30 AM
- - dmhzx   When it is addressed, I wonder if the following co...   Oct 12 2013, 12:30 PM
- - ace   While we're at it, a wiki article really shoul...   Oct 12 2013, 01:08 PM
- - genoma111   That's not even an abstract   Oct 12 2013, 02:56 PM
- - CyberCow   The beauty of our Wiki is that ANY member can add/...   Oct 12 2013, 04:16 PM
- - ButtonMoon   In relational database terms a table must have at ...   Oct 12 2013, 05:53 PM
- - genoma111   QUOTE (ButtonMoon)Any student wanting to learn abo...   Oct 12 2013, 06:43 PM
- - CyberCow   ButtonMoon - I agree with Diego. Making such a sta...   Oct 13 2013, 08:58 AM
- - ace   One could sit down in front of Access with a good ...   Oct 13 2013, 10:18 AM
- - argeedblu   Well said, Mark and Ace. That's the old saying...   Oct 13 2013, 10:23 AM
- - ButtonMoon   That's true but then why bother with Access at...   Oct 13 2013, 10:34 AM
- - ace   Can you make any suggestions?   Oct 13 2013, 10:36 AM
- - CyberCow   I believe the venue and end-target of what a stude...   Oct 13 2013, 11:06 AM
- - GroverParkGeorge   When I was studying linguistics back in the 70...   Oct 13 2013, 12:10 PM
- - CyberCow   George - very well said! order="0" alt="thumbu...   Oct 13 2013, 01:27 PM
- - genoma111   QUOTE (ButtonMoon)I'm simply saying that Acces...   Oct 13 2013, 03:01 PM
- - ButtonMoon   Hi George, You may be right. Many people using Acc...   Oct 14 2013, 05:54 AM
- - argeedblu   @ButtonMoon As Ace and Cybercow have already asked...   Oct 14 2013, 06:09 AM
- - genoma111   QUOTE (ButtonMoon)More worrying to me is the tende...   Oct 14 2013, 06:42 AM
- - ButtonMoon   Access is a fine application developer's tool....   Oct 14 2013, 07:44 AM
- - BananaRepublic   While it would be nice that everyone learned every...   Oct 14 2013, 08:34 AM
- - doctor9   ButtonMoon, Sorry, I have to disagree here. That...   Oct 14 2013, 08:47 AM
- - BananaRepublic   FYI: Regarding the side topic about inability to p...   Oct 14 2013, 09:36 AM
- - ButtonMoon   That's good news. Thanks.   Oct 14 2013, 09:46 AM
- - ace   I have to agree that if your goal is to learn rela...   Oct 14 2013, 12:01 PM
- - JonSmith   I am going to jump in and defend ButtonMoon abit. ...   Oct 14 2013, 01:09 PM
- - genoma111   QUOTE (JonSmith)The enterprise solutions listed ar...   Oct 14 2013, 05:13 PM
- - ButtonMoon   I have updated the article with some fuller explan...   Jan 10 2014, 01:38 AM
- - iliyanuhu   MicroSoft developed MS access and MS SQL Server (p...   Aug 20 2014, 10:17 AM
- - dmhzx   I like to think of myself as a pragmatist, and a ...   Aug 20 2014, 11:11 AM
- - datAdrenaline   >> But back to my original question, is ther...   Aug 20 2014, 01:14 PM
- - ace   A key is theoretical. An index is physical.   Aug 20 2014, 02:17 PM
- - GroverParkGeorge   @ iliyanuhu. Either your question is based on a fa...   Aug 20 2014, 03:14 PM
- - CyberCow   iliyanuhu - I consider such 'presumptions...   Aug 26 2014, 11:58 PM
- - haresfur   Ok, so if I understand this properly, a key unique...   Sep 2 2014, 10:48 PM
- - argeedblu   I hope this reply will clear the water for you and...   Sep 3 2014, 02:40 AM
- - ace   The Minimal suggestion refers to when a key is con...   Sep 3 2014, 05:26 AM
- - haresfur   Thanks Glenn and Ace, This is helpful and I believ...   Sep 3 2014, 11:21 PM
- - argeedblu   Hi Evan, I'm glad that Ace and I were able to ...   Sep 4 2014, 02:25 AM
- - ace   You have to at least identify a natural key in ord...   Sep 4 2014, 05:53 AM
- - haresfur   Thanks again, this is most helpful. I was thinking...   Sep 7 2014, 07:30 PM
- - ace   How else would it be done? When you define a ...   Sep 7 2014, 07:57 PM
- - CyberCow   Regina Whip has a fresh blog post out on Sequentia...   Sep 7 2014, 09:07 PM
- - datAdrenaline   Some terms to note ... Key: a field (attribute) or...   Sep 7 2014, 09:35 PM



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