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What does the comment "hopefully PK-preserving" mean? Please explain. -- MauriceKA 09:36, 17 Mar 2005 (UTC)
Preserving privacy while using authorization certificates ?
Shouldn't this article reference ROLAP, MOLAP, and HOLAP cubes as well? 65.202.85.9 15:23, 11 January 2007 (UTC)
Can someone please explain the functional notation here? I believe it should be f: (X, Y, Z) |--> W, not W: (X, Y, Z) |--> W. Ericdbw 06:15, 16 September 2007 (UTC)
I agree. I've changed it. Qseep ( talk) 00:08, 10 February 2011 (UTC)
Why does this article need sources? It's not as if the source would be any more reputable anyway. —Preceding unsigned comment added by 128.237.241.67 ( talk) 03:34, 18 February 2008 (UTC)
{{
cite web}}
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help)I will take it on myself to work on properly adding the references on this article. Anyone want to help? Kgrr ( talk) 18:54, 5 March 2008 (UTC)
I've added a reference to the Technical section citing the 1995 paper by Gray et al as providing the technical definition of an OLAP Cube, though the terminology in that paper was slightly different ("Data-Cube"). This paper received the 2005 Influential Paper award from the ICDE, identifying it as foundational or instrumental in the creation of OLAP. I suspect that the "motivation" citation is no longer needed, as the above paper also lays-out the motivations, but I have left that edit undone for now pending discussion here. Gyrae ( talk) 06:04, 9 November 2008 (UTC)
This needs to be included in the article:
The OLAP cube consists of numeric facts called measures which are categorized by dimensions. The cube metadata is typically created from a star schema or snowflake schema of tables in a relational database. Measures are derived from the records in the fact table and dimensions are derived from the dimension tables. Kgrr ( talk) 11:55, 18 March 2008 (UTC)
The timestamp example does not clearly explain the benefit of assigning an ID value to a timestamp when the timestamp itself could be used. It seems like useless abstraction. Could someone more knowledgeable provide a more clear example? —Preceding unsigned comment added by 24.165.146.46 ( talk) 02:32, 13 June 2009 (UTC)
Text says: An OLAP (Online analytical processing) cube is a data structure that allows fast analysis of data. It can also be defined as the capability of manipulating and analyzing data from multiple perspectives. This is followed by a reference to an article by Codd. I have the following issues with the above:
The section goes on to say that "Relational databases are not well suited for near instantaneous analysis and display of large amounts of data", despite the existence of ROLAP and the fact that some proponents of the relational model think performance is a red-herring (after factoring in the need for integrity constraints processing outside of the DBMS). For example, see http://www.information-management.com/issues/20020601/5251-1.html. So I don't think this sentence is well founded. At a minimum it needs a reference and I have marked it up as dubious/citation needed.
The following sentence is presented as a statement of fact, but does not provide any references: "Although many report-writing tools exist for relational databases, these are slow when the whole database must be summarized." The problems I have with this statement are:
I think Microsoft MSDN page provides a better explanation to what an OLAP cube is. I have attached the link here. I am not sure if we could use the information from this link to update the Introduction. Database experts can please verify this. Thank you. Link : Microsoft MSDN Article -- Abdul Jabbar 09:27, 28 April 2010 (UTC) ( talk)
Language like
The arrangement of data into cubes overcomes a limitation of relational databases. Relational databases are not well suited for near instantaneous analysis and display of large amounts of data.
sounds like an advertisement, not NPOV. Crasshopper ( talk) 05:05, 2 March 2010 (UTC)
Sounds factual to me, doesn't a cube's creation implicitly preprocesses a lot of the possible selections therefore greatly reducing selection time at a later time? So if the data is maintained in a cube format, selections from it will be fast.
131.111.202.114 ( talk) 13:14, 13 March 2010 (UTC)
As a newbie to OLAP, when I read the sentence about RD not being suited for instantaneous analysis, my first question was "so how do you implement it". Later on in the article, it says that you implement it in a relational database... The claim needs at least some explanation, where it stands in the text. I can't disagree completely with the marketing talk claim, since I have implemented relational models on non-relational flat file databases using tricks, and I wouldn't say that this fact makes relational databases the same as, say a flat file database. The fact that an OLAP cube CAN be implemented on a relational database does not make it an analogous concept to a relational database. From the abstract description of the OLAP cube, it is not clear that it must be implemented on a relational database; and I'm guessing that in fact it can be implemented otherwise. 62.233.239.26 ( talk) 06:20, 7 May 2010 (UTC)J
It sounds to me like OLAP Cubes are an abstract data concept. It may be that certain implementations are designed to be efficient at certain actions but I'd want to see citations (from something other than product marketing material). Also, reference #4 -- cited to back-up claims about efficiency of OLAP vs RDBMS -- is a link to an answers.com page which is, at least now, almost entirely just a copy of the wikipedia doc. I see nothing there of relevance. 83.67.12.45 ( talk) 07:52, 16 May 2010 (UTC)
From what I know, OLAP would use Star and Snowflake schema. These would be much less normalized than schemas use in Operational Relational Databases. They would not enforce/check for constraints such as uniqueness, foriegn key references etc making them faster than Operational Relational Databases even if they are implemented using RDBs
nishantjr ( talk) 10:42, 15 June 2010 (UTC)
This article currently links to residual, which is a disambiguation page. The link needs to get replaced by [[WHATEVER|residual]]. Michael Hardy ( talk) 19:59, 5 May 2011 (UTC)
Looking at the images, they contain text that is not in English. Looks like German to me, or some nordic language perhaps. Can anybody translate them? Thanks. The 11th plague of Egypt ( talk) 15:42, 21 March 2014 (UTC)
The unmathematical definitions on this article confuse me. In the "Mathematical definition" section, f is not defined, so it might be anything including the identity function (W is not defined either). So is the cube just an Rn or Xn space, or a multidimensional array? -- Nemo 14:13, 9 June 2015 (UTC)
Seems to me we're really talking about hyperrectangles, not hypercubes, but if the industry has accepted 'hypercube', we're too late. Not the first time I've seen this conflation. Wootery ( talk) 17:21, 4 February 2018 (UTC)
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||
|
What does the comment "hopefully PK-preserving" mean? Please explain. -- MauriceKA 09:36, 17 Mar 2005 (UTC)
Preserving privacy while using authorization certificates ?
Shouldn't this article reference ROLAP, MOLAP, and HOLAP cubes as well? 65.202.85.9 15:23, 11 January 2007 (UTC)
Can someone please explain the functional notation here? I believe it should be f: (X, Y, Z) |--> W, not W: (X, Y, Z) |--> W. Ericdbw 06:15, 16 September 2007 (UTC)
I agree. I've changed it. Qseep ( talk) 00:08, 10 February 2011 (UTC)
Why does this article need sources? It's not as if the source would be any more reputable anyway. —Preceding unsigned comment added by 128.237.241.67 ( talk) 03:34, 18 February 2008 (UTC)
{{
cite web}}
: Check date values in: |date=
(
help)I will take it on myself to work on properly adding the references on this article. Anyone want to help? Kgrr ( talk) 18:54, 5 March 2008 (UTC)
I've added a reference to the Technical section citing the 1995 paper by Gray et al as providing the technical definition of an OLAP Cube, though the terminology in that paper was slightly different ("Data-Cube"). This paper received the 2005 Influential Paper award from the ICDE, identifying it as foundational or instrumental in the creation of OLAP. I suspect that the "motivation" citation is no longer needed, as the above paper also lays-out the motivations, but I have left that edit undone for now pending discussion here. Gyrae ( talk) 06:04, 9 November 2008 (UTC)
This needs to be included in the article:
The OLAP cube consists of numeric facts called measures which are categorized by dimensions. The cube metadata is typically created from a star schema or snowflake schema of tables in a relational database. Measures are derived from the records in the fact table and dimensions are derived from the dimension tables. Kgrr ( talk) 11:55, 18 March 2008 (UTC)
The timestamp example does not clearly explain the benefit of assigning an ID value to a timestamp when the timestamp itself could be used. It seems like useless abstraction. Could someone more knowledgeable provide a more clear example? —Preceding unsigned comment added by 24.165.146.46 ( talk) 02:32, 13 June 2009 (UTC)
Text says: An OLAP (Online analytical processing) cube is a data structure that allows fast analysis of data. It can also be defined as the capability of manipulating and analyzing data from multiple perspectives. This is followed by a reference to an article by Codd. I have the following issues with the above:
The section goes on to say that "Relational databases are not well suited for near instantaneous analysis and display of large amounts of data", despite the existence of ROLAP and the fact that some proponents of the relational model think performance is a red-herring (after factoring in the need for integrity constraints processing outside of the DBMS). For example, see http://www.information-management.com/issues/20020601/5251-1.html. So I don't think this sentence is well founded. At a minimum it needs a reference and I have marked it up as dubious/citation needed.
The following sentence is presented as a statement of fact, but does not provide any references: "Although many report-writing tools exist for relational databases, these are slow when the whole database must be summarized." The problems I have with this statement are:
I think Microsoft MSDN page provides a better explanation to what an OLAP cube is. I have attached the link here. I am not sure if we could use the information from this link to update the Introduction. Database experts can please verify this. Thank you. Link : Microsoft MSDN Article -- Abdul Jabbar 09:27, 28 April 2010 (UTC) ( talk)
Language like
The arrangement of data into cubes overcomes a limitation of relational databases. Relational databases are not well suited for near instantaneous analysis and display of large amounts of data.
sounds like an advertisement, not NPOV. Crasshopper ( talk) 05:05, 2 March 2010 (UTC)
Sounds factual to me, doesn't a cube's creation implicitly preprocesses a lot of the possible selections therefore greatly reducing selection time at a later time? So if the data is maintained in a cube format, selections from it will be fast.
131.111.202.114 ( talk) 13:14, 13 March 2010 (UTC)
As a newbie to OLAP, when I read the sentence about RD not being suited for instantaneous analysis, my first question was "so how do you implement it". Later on in the article, it says that you implement it in a relational database... The claim needs at least some explanation, where it stands in the text. I can't disagree completely with the marketing talk claim, since I have implemented relational models on non-relational flat file databases using tricks, and I wouldn't say that this fact makes relational databases the same as, say a flat file database. The fact that an OLAP cube CAN be implemented on a relational database does not make it an analogous concept to a relational database. From the abstract description of the OLAP cube, it is not clear that it must be implemented on a relational database; and I'm guessing that in fact it can be implemented otherwise. 62.233.239.26 ( talk) 06:20, 7 May 2010 (UTC)J
It sounds to me like OLAP Cubes are an abstract data concept. It may be that certain implementations are designed to be efficient at certain actions but I'd want to see citations (from something other than product marketing material). Also, reference #4 -- cited to back-up claims about efficiency of OLAP vs RDBMS -- is a link to an answers.com page which is, at least now, almost entirely just a copy of the wikipedia doc. I see nothing there of relevance. 83.67.12.45 ( talk) 07:52, 16 May 2010 (UTC)
From what I know, OLAP would use Star and Snowflake schema. These would be much less normalized than schemas use in Operational Relational Databases. They would not enforce/check for constraints such as uniqueness, foriegn key references etc making them faster than Operational Relational Databases even if they are implemented using RDBs
nishantjr ( talk) 10:42, 15 June 2010 (UTC)
This article currently links to residual, which is a disambiguation page. The link needs to get replaced by [[WHATEVER|residual]]. Michael Hardy ( talk) 19:59, 5 May 2011 (UTC)
Looking at the images, they contain text that is not in English. Looks like German to me, or some nordic language perhaps. Can anybody translate them? Thanks. The 11th plague of Egypt ( talk) 15:42, 21 March 2014 (UTC)
The unmathematical definitions on this article confuse me. In the "Mathematical definition" section, f is not defined, so it might be anything including the identity function (W is not defined either). So is the cube just an Rn or Xn space, or a multidimensional array? -- Nemo 14:13, 9 June 2015 (UTC)
Seems to me we're really talking about hyperrectangles, not hypercubes, but if the industry has accepted 'hypercube', we're too late. Not the first time I've seen this conflation. Wootery ( talk) 17:21, 4 February 2018 (UTC)