von Nasrullah Memon
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| [1.] Nm/Fragment 208 01 - Diskussion Zuletzt bearbeitet: 2012-04-26 08:16:48 Fiesh | BauernOpfer, Fragment, Frost 1982, Gesichtet, Nm, SMWFragment, Schutzlevel sysop |
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| Untersuchte Arbeit: Seite: 208, Zeilen: 1-10 |
Quelle: Frost 1982 Seite(n): 359, Zeilen: right column 20-28 |
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* Simple interface between a binary relational storage structure and other modules of a database management system consists of three procedures:
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Simple interface with other modules
Interface between a binary-relational storage structure and other modules of a database management system consists of three procedures: (i) insert (triple); (ii) delete (partial specification of triple); (iii) retrieve (partial specification of triple). Retrieval requests such as 'list all employees of IBM' are met by issuing a simple retrieval call (IBM. employs. ?) which delivers only that data which has been requested |
The source is named on the previous page. Nevertheless it is not to be expected that Nm, follows it word-for-word, given there are no quotation marks. |
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| [2.] Nm/Fragment 208 11 - Diskussion Zuletzt bearbeitet: 2012-04-16 22:12:08 Hindemith | Fragment, Frost 1982, Gesichtet, Nm, SMWFragment, Schutzlevel sysop, Verschleierung |
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| Untersuchte Arbeit: Seite: 208, Zeilen: 11-15, 17-18, 24-28 |
Quelle: Frost 1982 Seite(n): 360-361, Zeilen: p.360, right column 51-56 & p.361, left column, 1-2.9-14 |
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| It is to be noted that multi-attribute retrieval may be inefficient. The use of binary relational structure for multi-attribute retrieval might not be the most efficient method (irrespective of the way in which the structure is implemented. To illustrate this, consider the example: “retrieve (the names of) all young (25 years old) married terrorists involved in 9/11 attacks who attended flight schools and got terrorist training in Afghanistan”. Using binary-relational structure, one could issue the retrievals:
(? .marital status. Married)
and merge the resultant sets to obtain the required data. This is probably much faster than having to do a sequential search through the whole database, which would be necessary if the database were held as a file of records (name, age, marital status, etc.) ordered on name. |
[p. 360]
Multi-attribute retrieval may be inefficient Use of a binary-relational structure for multi-attribute retrieval might not be the most efficient method (irrespective of the way in which the structure is implemented). To illustrate this, consider the example given by Martin[EN 12]: 'retrieve (the names of) all 18 year old unemployed actresses with experience in movie-acting, [p. 361] and talents for singing and sky-diving'. Using a binary relational structure, one could issue the retrievals: (?. aged. 18)
and merge the resultant sets to obtain the required data. This is probably much faster than having to do a sequential search through the whole database, which would be necessary if the database were held as a file of records (name, age, job-status, profession, experience, talents) ordered on name. |
Continues the copying from Frost (1982). The example given seems to be one of Nm's own making. |
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Letzte Bearbeitung dieser Seite: durch Benutzer:Hindemith, Zeitstempel: 20120416221655