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Foreign Key implementation on GLUE 2.0 LDAP implementation
by David Horat 16 Apr '09

16 Apr '09

Hello all, After having a talk with Maarten, a few emails with Laurence, seen the GLUE 1.3 LDAP implementation on lcg-bdii.cern.ch and though about it thoroughly, I have come to the next idea for implementing Foreign Keys on LDAP: Having an object ObjectA related to object ObjectB and being the relationship ObjectA 0..* - 0..* ObjectB, - ObjectA will contain the attribute ObjectAObjectBFK pointing to ObjectB's DN - ObjectB will contain the attribute ObjectBObjectAFK pointing to ObjectA's DN - In case the multiplicity was 1..X, with X between 1 and *, ObjectYObjectZFK will be mandatory - In case the multiplicity was 1 or 0..1, ObjectYObjectZFK will be SINGLE-VALUE - In case the relationship was Object A 0..* - 1 Object B, ObjectA will be the only one holding the ForeignKey Since LDAP is not relational, there are a few pitfalls with LDAP: - ObjectYObjectZFK is not checked to be the correct - The duality ObjectAObjectBFK and ObjectBObjectAFK is not checked to have the relation stated in both directions - Moving between relations is done in the client and not the server, which is not optimal These should be checked in an external client at appropriate invertals to ensure the integrity of the LDAP server plus all the specifcations done in GLUE 2.0 that can not be covered in LDAP (types, maximum range, etc.). I would like to have an approval of 1 or 2 people before starting with it. So, do you like it this way? :) Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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LDAP Rendering
by Laurence Field 16 Apr '09

16 Apr '09

David Horat from CERN will start looking at the LDAP schema rendering. Does anyone have any comment/suggestions before he gets started? Laurence

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Question about Entity and its relationship with Extension
by David Horat 16 Apr '09

16 Apr '09

In the GLUE Specification v. 2.0, page 8, it is specified the Entity class. In its "Association.End" there is just one field: "Extension.Key", but in the Extension class, its unique identifier is "LocalId". So in the Entity class, it should be specified "Extension.LocalId" instead of "Extension.Key". "Extension.Key" shouldn´t be used because of its description, which I quote here: "This identifier is not required to be unique; several instances of this class MAY hold the same value of this attribute". So this could be another erratum, isn´t it? Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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More on location: WOEID
by Paul Millar 15 Apr '09

15 Apr '09

Hi all, There's an interesting audio interview with Tyler Bell on O'Reilly Radar about how to specify geographical location. In the interview, Tyler talks about Yahoo's approach: http://radar.oreilly.com/2009/04/where-20-preview---tyler-bell.html In brief, they define a unique 32-bit number to each location: the "Where On Earth ID" or "WOEID". They also provide a public, restful API to query their database to extract metadata about the area. Details are available here: http://developer.yahoo.com/geo/ http://developer.yahoo.com/geo/guide/ One of the nice features of this is one can express low-granularity information (such as a city, county or country) without having to specify a (potentially meaningless) centroid lat./long. ordered pair. This is nice as they also expose their semantic structure, so one can (for example) discover that Canada is within the United States. I propose in the next version of GLUE we add an optional field called woeid so people have a standard field to include the WOEID, if they choose to do so. Cheers, Paul.

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Question about LocalId_t
by David Horat 30 Mar '09

30 Mar '09

Hello guys, The LocalId attribute of the Extension class specified in page 8 of the GLUE 2.0 Specifications is of type LocalId_t. The LocalId_t is specified in page 72, which basically says that is must be a string that starts with a-zA-Z and the following characters can be into a-zA-Z_0-9. I am just curious to know why did you apply this restriction. I am sure there is a good reason behind it. Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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Tighten defn of Country property?
by Paul Millar 30 Mar '09

30 Mar '09

Hi all, Current defn of Location.Country is simply "Name of country." However, this can lead to confusion. Is the United States of America "US", "USA", "United States", "United States of America"? Is the United Kingdom represented by "GB", "GBR", "UK", "U.K." etc. Perhaps we should clarify this. I would change the definition to: Name of country. The value SHOULD be the country's ISO 3166-1 Alpha-3 code. (we could use any code, but ISO 3166-1 Alpha-3 seems appropriate). Cheers, Paul.

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Question about the way of specifying relationships
by David Horat 27 Mar '09

27 Mar '09

In the GLUE Specification v. 2.0, in the association end list, relations are always specified with the attribute they have to link with. (E.g. Service.ID) This is not correct because of several reasons: - In the Entity-Relationship models, you just specify relationship between entities/classes/objects, without any knowledge of each of the attributes in them. - To know which attribute you want to link with from the related object, you should have to take a look of its definition to get the key fields. - The key fields could be more than one. Sometimes the key of an entity is a combination of several fields, so the current way of visualizing relations will be broken. I suggest just taking out every attribute in all the Association End list to comply on how to use this kind of diagrams, to avoid problems in the future with multiple key fields. Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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Admin needed: Lack of permissions commiting to GLUE SVN
by David Horat 25 Mar '09

25 Mar '09

Hello all, I just tried to commit for the first time to the GLUE SVN and this is what it happens: horat@horat-hpnc6220:~/gridsrc/glue$ svn commit --username horat svn: Commit failed (details follow): svn: Server sent unexpected return value (403 Forbidden) in response to MKACTIVITY request for '/svn/repos/glue/!svn/act/1e158427-8963-49f4-8251-ec5b4fb8bb27' It seems that the *authentication* succeeded, but the *authorization* was unsuccessful, thus it may be due to a lack of permissions. Can any admin give me permissions to commit to the GLUE repository? My username is "horat". Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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Question about multiplicity in GLUE 2.0 Specification
by David Horat 25 Mar '09

25 Mar '09

Hello all! :) On GLUE 2.0 Specification v. 2.0 from 3rd March 2009, which is the latest, I see that the multiplicity field is specified as '*', '0..*' or '1..*'. I assume that '*' is the same as '0..*' as this is the standard convention. Anyway it should be good to concrete it for every field and just have either '0..*' or '1..*'. So, is this specification still open for little changes like this? Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat

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Implementations page
by Sergio Andreozzi 05 Mar '09

05 Mar '09

dear all, based on the yesterday GLUE implementation session, I've drafted a wiki page where all the implementation activities can be tracked: http://forge.ogf.org/sf/wiki/do/viewPage/projects.glue-wg/wiki/ListOfImplem… Please, fill the missing fields or add more lines where it applies. Cheers, Sergio

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