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Topic: 3NF

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	Database Resource
		It therefore follows it cannot be in 3NF or BCNF, so it must be in either 0NF or 1NF.
		In this case, to NOT be in 3NF, e,f,g would have to be involved in selecting a subset of h,i,j.
		Thus this relation IS NOT in 3NF, and thus cannot be in 4NF or BCNF.
	db.grussell.org /mc/q38.html (217 words)

	Chapter 5 (Site not responding. Last check: 2007-10-14)
		To convert the table structure in Figure 5-6 to structures that are in 3NF and BCNF, it is appropriate to first change the primary key to __________.
		Although 3NF is usually sufficient in a business environment, there are some circumstances that may require the use of a higher-level normal form.
		A condition in which an attribute is dependent on another attribute, where the latter is not part of the primary key, is known as a(n) ___________.
	www.westol.com /martzr/cpt_235/chap_5.htm (1729 words)

	The Office Experts Forums - 3nf
		3nf just requires that all the stored data be tied back to the primary key.
		Is there a non calculated field that could be added to the table that would not comply to 3nf.
		Since the requirement for 3nf is that fields must depend ONLY on the key, a field that depends on any field that is not part of the key would render a table NON-3nf.
	www.theofficeexperts.com /forum/showthread.php?t=3087 (689 words)

	Schema Modeling Techniques (Site not responding. Last check: 2007-10-14)
		Additionally, some data warehouse schemas are neither star schemas nor 3NF schemas, but instead share characteristics of both schemas; these are referred to as hybrid schema models.
		3NF schemas are typically chosen for large data warehouses, especially environments with significant data-loading requirements that are used to feed data marts and execute long-running queries.
		Queries on 3NF schemas are often very complex and involve a large number of tables.
	www.lc.leidenuniv.nl /awcourse/oracle/server.920/a96520/schemas.htm (2553 words)

	Relational Model: Normalization
		A relational table is in 3NF if and only if all non-key columns are (a) mutually independent and (b) fully dependent upon the primary key.
		A relational table is in third normal form (3NF) if it is already in 2NF and every non-key column is non transitively dependent upon its primary key.
		The advantage of having relational tables in 3NF is that it eliminates redundant data which in turn saves space and reduces manipulation anomalies.
	www.utexas.edu /its/windows/database/datamodeling/rm/rm7.html (1397 words)

	TDAN Linstedt - Data Vault
		Performance and other weaknesses of 3NF and star schema (when used within an enterprise data warehouse) began to show in the 90’s as the volume of data increased.
		3NF and star schema when used for enterprise data warehousing may cause pain to the business because they were not built originally for this purpose.
		The current data models based on 3NF or star schema are proving difficult to modify, maintain and query, let alone backup and restore.
	www.tdan.com /i021hy01.htm (4746 words)

	Third Normal Form (3NF) (Site not responding. Last check: 2007-10-14)
		The 3NF differs from the 2NF in that all non-key attributes in 3NF are required to be directly dependent on each candidate key of the relation.
		The 3NF therefore insists, in the words of Kent (1983) that all facts in the relation are about the key (or the thing that the key identifies), the whole key and nothing but the key.
		The relation is however not in 3NF since office is not directly dependent on cno.
	www.cs.jcu.edu.au /Subjects/cp1500/1998/Lecture_Notes/normalisation/3nf.html (513 words)

	Relational Model: Advanced Normalization (Site not responding. Last check: 2007-10-14)
		After 3NF, all normalization problems involve only tables which have three or more columns and all the columns are keys.
		Many practitioners argue that placing entities in 3NF is generally sufficient because it is rare that entities that are in 3NF are not also in 4NF and 5NF.
		Boyce-Codd normal form (BCNF) is a more rigorous version of the 3NF deal with relational tables that had (a) multiple candidate keys, (b) composite candidate keys, and (c) candidate keys that overlapped.
	www.utexas.edu /its/windows/database/datamodeling/rm/rm8.html (727 words)

	Type Your Title Here
		3NF specifies that every non-key attribute is non- transitively dependent on the primary key.
		Normalization past 3NF does not occur often in normal practice because most tables in 3NF are usually also in 5NF.
		Forget about it! Normalization is for academics and in its strictest form is generally impractical due to its adverse effect on performance in a commercial environment, especially 3NF, 4NF and 5NF.
	www.inconcept.com /JCM/September2004/Pascal.html (1327 words)

	Midrange Programmer
		You will find the majority of tables in most iSeries applications are in 3NF, which is usually a good balance between performance and database flexibility.
		By reaching 3NF, we can accurately state that all non-key attributes in the table are related to the key, the whole key, and nothing but the key.
		History files often tend to be normalized to a lower degree (i.e., 2NF) for the sake of performance.
	www.itjungle.com /mpo/mpo091103-story02.html (1200 words)

	Normal Form Definitions & Examples
		A relation R having just one candidate key is in third normal form (3NF) if and only if the non-key attributes of R (if any) are: 1) mutually independent, and 2) fully dependent on the primary key of R. A non-key attribute is any column which is not part of the primary key.
		Since relations in 3NF but not in BCNF are slightly unusual, it is a bit more difficult to come up with meaningful examples.
		The relation is also in 3NF since even though the non-primary-key column supplier_name determines the non-key columns city and zip, supplier_name is a candidate key.
	www.yk.psu.edu /~lxn/IST_210/normal_form_definitions.html (923 words)

	Intelligent Enterprise Magazine (Site not responding. Last check: 2007-10-14)
		I did also note that the 3NF definition in particular wasn't entirely satisfactory in its original form, owing to its reliance on the concept of nonprime attributes.
		C3 is in optimal 3NF relative to C2 if (a) no relation in C3 has a pair of attributes A and C such that C is strictly transitively dependent on A in some relation in C2 and (b) C3 contains the fewest possible relations consistent with condition (a).
		Let me also remind you of Codd's original definition of 3NF: Relation R is in 3NF if it's in 2NF and every nonprime attribute is nontransitively dependent on each candidate key of R. Now let's take a look at an example.
	www.intelligententerprise.com /db_area/archives/1999/992004/online2.jhtml (1849 words)

	dataWarehouse.com \| Brought to you by DM Review (Site not responding. Last check: 2007-10-14)
		A table may be in 3NF, but not in BCNF.
		Like 2NF and 3NF, but unlike the advanced normal forms, BCNF is concerned with functional dependencies.
		The table is in 3NF because there are no transitive dependencies from one non-key attribute to another.
	www.datawarehouse.com /article?articleid=2993 (2357 words)

	Systems Analysis and Design Case Studies
		For a table to be in 3NF it MUST be in 1NF and 2NF.
		3NF (Third Normal Form) : A table is in 3NF if it is in 2NF and all the non-key fields depend only on the primary key, the whole primary key and nothing but the whole primary key.
		Readers should note that even if the non-key field "A" depends on the primary key "C", the table may not be in 3NF if "A" also depends on a non-key field "B".
	www.homepages.com.pk /kashman/Ch8.htm (2469 words)

	Photodisintegration of 3He
		H, and have shown remarkable sensitivities to 3NF effects in the differential cross section.
		Moreover, this group is now beginning a series of calculations for polarized-photon beams to investigate the sensitivity to 3NF effects in the photon-beam asymmetry.
		While the Blowfish detector is ideal for neutron measurements, it is not sufficient for charged-particle detection, where protons or deuterons will have difficulty exiting from a thick-walled high-pressure gas target.
	www.gwu.edu /~ndl/research6jj.htm (1366 words)

	3NF \| MySmartChannels (Site not responding. Last check: 2007-10-14)
		After today's class, i finally understood that 3NF does not mean that we have a situation where C depends on B, and B depends on A. Prior to today's class, i thought the normalization process could theoretically go on forever,...
		After today's class, i finally understood that 3NF does not mean that we have a situation where C depends on B, and B depends on A. Prior to today's class, i thought the normalization process could theoretically go on forever, to XNF.
		It is good to see the example where 2NF is the same as the 3NF.
	myst-technology.com /mysmartchannels/public/item/59294 (180 words)

	APPENDIX D: NORMAL FORMS
		3NF but not BCNF because we had to use the escape clause.
		But 3NF allows a non-key on the l.h.s.
		This is 3NF but not BCNF because B is not a key and A is prime.]
	www.sci.csuhayward.edu /~billard/case/node10.html (272 words)

	COS 425, Spring 2001 : 3NF algorithm -- proof works
		Let mcF denote the minimal cover of a set of functional dependencies F within a relation R. Suppose we have a set of relations that have been obtained by the decomposition of R using mcF such that all the relations are now in 3NF.
		Proof: We need to show that relation with schema XA is in 3NF with respect to the projection of mcF on XA.
		If Y does not contain A, then the attributes of Y must be a subset of the attributes of X, which means X->A is not minimal.
	www.cs.princeton.edu /courses/archive/spr01/cs425/3nfproof.html (318 words)

	3nf design
		If no proper subset of F' is a cover for F, then F' is said to be a minimal cover for F.
		Minimal covers are not unique: for 3NF design we use a particular kind of minimal cover, called a canonical cover.
		3NF Schema = {(A,B), (B,D), (C,D), (A,E,F)} with respective keys, A, B, both C and D, and AEF.
	www.cs.ucla.edu /classes/fall04/cs143/notes/3nf.html (375 words)

	3nf (Site not responding. Last check: 2007-10-14)
		Second Normal Form (or 2NF) requires that there are no non-trivial functional dependencies of a non-key attribute on a part of a candidate key.
		Third Normal Form (or 3NF) requires that there are not non-trivial functional dependencies of non-key attributes on something else than a superset of a candidate key.
		Boyce-Codd Normal Form (or BCNF) requires that there are no non-trival functional dependencies of attributes on something else than a superset of a candidate key.
	www.yourencyclopedia.net /3NF.html (1434 words)

	Month Year Issue
		A table is in 3NF if it is in 2NF and no non-key attributes are dependent on other non-key attributes.
		Elementary Key Normal Form (EKNF) is a subtle enhancement on 3NF (by definition, EKNF tables are also in 3NF) that most often occurs when there is more than one unique composite key (more than one column) which overlap (one or more columns are involved in both keys) in a table 3.
		It is important to note that while the normal forms are subsets of each other (for example, a schema in 3NF is in 2NF by definition) it is not necessary to move from one to the other in a sequential fashion.
	www.inconcept.com /JCM/June1999/becker.html (3290 words)

	Comparison of BCNF and 3NF (Site not responding. Last check: 2007-10-14)
		It is always possible to obtain a 3NF design without sacrificing lossless-join or dependency-preservation.
		If we must choose between BCNF and dependency preservation, it is generally better to opt for 3NF.
		The limited amount of redundancy in 3NF is then a lesser evil.
	www.cs.sfu.ca /CC/354/zaiane/material/notes/Chapter7/node12.html (190 words)

	Transact-SQL Programming -- Sample chapter
		A 3NF table should provide a single-value fact about the key and should use the whole key (if concatenated), and nothing but the key, to derive its uniqueness.
		Third Normal Form (3NF) refers only to tables with a single-key field and requires that each non-key field be a direct description of the primary key field.
		There are additional steps in normalization used to solve other specific logic faults in table design; however, they are seldom practical in the use of nonacademic applications.
	www.oreilly.com /catalog/wintrnssql/chapter/ch01.html (7245 words)

	Third Normal Form (Site not responding. Last check: 2007-10-14)
		A relation schema R is in 3NF with respect to a set F of functional dependencies if for all functional dependencies in
		A database design is in 3NF if each member of the set of relation schemas is in 3NF.
		As all relation schemas in BCNF satisfy the first two conditions only, a schema in BCNF is also in 3NF.
	www.cs.sfu.ca /CC/354/zaiane/material/notes/Chapter7/node11.html (283 words)

	Normalization to 3NF using analysis (Site not responding. Last check: 2007-10-14)
		This is a small applet which builds a set of relations in 3NF based on a set of functional dependencies.
		It will break the universal relation into smaller relations which are all 3NF.
		By analysing the canonical FDSet the universal relation will be broken up until all relations are in 3NF.
	www.student.nada.kth.se /~d86-emh/dbt/lab2.html (221 words)

	Darrell Norton's Blog [MVP] : Third normal form (3NF) is not the end goal
		Third normal form (3NF) is not the end goal
		But his overall point about 3NF not being the goal is correct.
		The interesting thing to note is that the post office is actually transitioning to the long zip code instead of street name, city, state and zip due to the inherent problems of misspelling, etc. So eventually those dependent fields hopefully will be removed.
	codebetter.com /blogs/darrell.norton/archive/2003/06/24/334.aspx (384 words)

	Webscape GDL Studio - Tools (Site not responding. Last check: 2007-10-14)
		Created by 3NF Corporation, a partner company of Webscape, the 3NF GDL System is going to change the landscape of GDL.
		This is the first system to create GDL objects outside of the Graphisoft environment, and the only system that has the ability to work with large catalogs of GDL objects in a single database.
		Combining the power of the 3NF GDL System with Webscape's knowledge of GDL and the construction industry we will be able to increase the quality and value of GDL object catalogs exponentially.
	www.webscape.com /GDL/3nf (192 words)

	Untitled Normal Page
		Def 1: Special Def (E/N) "R is in 3NF if it’s in 2NF and all nonprime attributes of R are not
		Proof: Consider R, not in 3NF by Def 3:
		Def 4: "R is in 3NF if every non-prime attribute is both:
	www.nuc.berkeley.edu /waste/ieor115/lecture21/lecture21.html (206 words)

	3NF question
		01-08-05 12:45 PM Hello I am still not sure about meaning of 3NF Let's say I've got a table, named USERS: Id Login Pass Description Id was selected as a key, but login has to be unique, so it's also a key.
		Lastly, I get the impression that your question about the meaning of 3NF was caused by the question about two (or more) keys in a single table.
		I think that this is a long story in both relational and conceptual models.
	www.webservertalk.com /message869345-1.html (2289 words)

	Rare_3NF_English (Site not responding. Last check: 2007-10-14)
		Die 3NF hatte 3 Trioden, 4 Widerstaende und 2 Kondensatoren.
		Bilder des Empfaengers OE333, der mit einer 3NF bestueckt ist finden Sie in der (Taste Rarität).
		Yes here can be seen four of the famous 3NF tubes, brand new and with their own packing.
	www.radiomuseum-bocket.de /engl/E_nf_3.htm (360 words)

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