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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Please can any body explain me the difference between Area and Sets in IDMS with example. |
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PeterHolland
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Joined: 27 Oct 2009
Posts: 2481
Location: Netherlands, Amstelveen
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Already I had searched on this but i did not understood so i asked to tell difference between set and Area with example. If anybody can tell me about this topic because just now I have started learning IDMS. |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA
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The Wikipedia article is pretty clear. An IDMS set is a one-to-many relationship between records. An IDMS area is a preformatted file (or part of a file or parts of multiple files) used to physically store the data. So a set is data while an area is a partitioning of the files.
Perhaps if you explained where you're having trouble with the concepts? |
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| I want an example for this, so that I can understand it clerly. |
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dbzTHEdinosauer
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Joined: 20 Oct 2006
Posts: 6966
Location: porcelain throne
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rasnc,
find another line of work,
you obviously do not have adequate background education. |
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Sorry, I did not understood "find another line of work". Anyways if possible can you suggest me any good books in IDMS because i have been allocated in project of IDMS so want to know about this. |
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dbzTHEdinosauer
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Joined: 20 Oct 2006
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Location: porcelain throne
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| Quote: |
Logical Data Model:
...
The most distinctive structuring concept in the Codasyl model is the set. Not to be confused with a mathematical set, a Codasyl set represents a one-to-many relationship between records: one owner, many members. The fact that a record can be a member in many different sets is the key factor that distinguishes the network model from the earlier hierarchical model. As with records, each set belongs to a named set type (different set types model different logical relationships). Sets are in fact ordered, and the sequence of records in a set can be used to convey information. A record can participate as an owner and member of any number of sets.
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Storage
IDMS organizes its databases as a series of files. These files are mapped and pre-formatted into so-called areas. The areas are subdivided into pages which correspond to physical blocks on the disk. The database records are stored within these blocks.
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Now, if you don't know the difference between a 'logical data model'
and storage,
refer to my previous post. |
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Thanks got the concept, just a small doubt is the IDMS record will be in same format of the normally record which is being used in the normal Flat file. |
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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Thanks, I got bit idea about SET, AREA and RECORD. An IDMS area is a preformatted file (or part of a file or parts of multiple files) Each area can contain occurrences of one or more record type. In the IDMS each entity like company, department and Employee along with their attribute are considered as record. IDMS support one too many relationship, this relationship is defined as set. Suppose for example if we consider Department and Employee set , its one too many relation one DEPARTMENT can have many employee. Department have its own record type like DEPT-ID,DEPT-NAME etc its record type. For example Set DEPARTMENT and EMPLOYEE may be found under same area or set DEPARTMENT may be under the area DEMO and EMPLOYEE may be under the area EMPL. Please correct me if my understand is wrong  |
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Anuj Dhawan
Superior Member
Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India
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Rashmi,
You need to do a bit of reading, you've a link given to you and you have google as your friend. To start with, people around here expects, at least, you to have the basic knowledge of the matter you asked for. And if you don't know that and just starting with teh subject, you should at least show how many source of inforation you've already looked in - what manual did you refer and what makes you to raise your eye brows, with that kind of commitment many will be around to help you...fwiw. |
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rasnc
New User
Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Already i said just from 3 days i have started learning IDMS, I am not getting what exactly you are tellling. I told about set, area and record meaning thats all for that i am asking whether my understand is rite or wrong thats all |
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enrico-sorichetti
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Joined: 14 Mar 2007
Posts: 10873
Location: italy
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Yes, You are wrong!
idms ( or any dbms ) datasets do not have any relation with those that You call flat files
flat files contain only application data
idms ( or any dbms ) datasets contain application data and control data
tha application data is what You see and use, control data is what is used by the dbms in order to provide its services
what is that You do not understand in the area explanation posted by Dick ??
areas are just containers not related in any way to the logical view of the application data |
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rasnc
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Joined: 31 Dec 2009
Posts: 10
Location: Bangalore
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| Thanks a lot got |
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