EP0420424A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A method of information retrieval for a database system
Assignee: International Business Machines Corp
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Filing: 1990-09-05
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Granted: —
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Expires: 2010-09-05
Abstract
Abstract A database comprises a sequential file 15 and a transposed file 11 in external memory. A query specifies various keywords, which are used to access the transposed file. Data concerning the various keywords, and especially identifiers for retrieval objects containing the keywords, are loaded into main storage. Inside main storage this information is rearranged, so as to be able to rank the retrieval objects in terms the keywords they contain. Identifiers from this ordered list can then be used to access information from the sequential file, with only retrieval objects with high query scores being accessed.
Inventors
- 👤 Kinichi Mitsui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 01:08
CPC Classifications
G; G06; G06F; G06F16/00; G06F16/30; G06F16/33; G06F16/3331; G06F16/334; G06F16/3347; Y; Y10; Y10S; Y10S707/00; Y10S707/99931; Y10S707/99933; Y10S707/99935
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
192 words
In a database system including: a sequential file (15) in external storage from which data relating to a retrieval object are outputted by inputting an identifier for said retrieval object; a transposed file (11) in external storage containing data, including identifiers, relating to retrieval objects that include a specified access key, and from which said data are outputted by inputting the specified access key; and query inputting means for inputting a query expressed as a combination of specified access keys with given weighting coefficients, and the number n of retrieval objects to be outputted; an information retrieval method comprising the following steps: in response to the input of a query, accessing the transposed file for each access key in the inputted query, and copying into main storage data (12) from the transposed file that relates to said each access key; calculating a query score for each retrieval object, based on the contents of the inputted query and the data copied from the transposed file; establishing the n retrieval objects (14) with the highest query score; and accessing the sequential file using the identifiers of said retrieval objects with the highest query score.
Claim 2
Dependent Claim
192 words
In a database system including: a sequential file (15) in external storage from which data relating to a retrieval object are outputted by inputting an identifier for said retrieval object; a transposed file (11) in external storage containing data, including identifiers, relating to retrieval objects that include a specified access key, and from which said data are outputted by inputting the specified access key; and query inputting means for inputting a query expressed as a combination of specified access keys with given weighting coefficients, and the number n of retrieval objects to be outputted; an information retrieval method comprising the following steps: in response to the input of a query, accessing the transposed file for each access key in the inputted query, and copying into main storage data (12) from the transposed file that relates to said each access key; calculating a query score for each retrieval object, based on the contents of the inputted query and the data copied from the transposed file; establishing the n retrieval objects (14) with the highest query score; and accessing the sequential file using the identifiers of said retrieval objects with the highest query score.
Claim 3
Dependent Claim
63 words
A method as claimed in claim 1, further including the steps of: preparing a transposed table (32) in main storage from the data copied into main storage from the transposed file; and preparing a sequential table (34) in main storage by interchanging the rows and columns of the transposed table, and using the data therein during said step of calculating the query scores.
Claim 4
Independent Claim
161 words
A method as claimed in any preceding claim, further comprising: selecting access keys from the inputted query for said accessing the transposed file, based on the values of said given weighting coefficents, the data that relates to the selected access key being copied into main storage; in response to the copying of data from the transposed file into main storage, calculating both the instantaneous query score and the maximum anticipated final query score for each retrieval object, based on the contents of the inputted query and the data copied from the transposed file; and stopping the selection of access keys when the retrieval object with the n th largest instantaneous query score has an instantaneous query score larger than the maximum anticipated final query score of each retrieval object having an instantaneous query score less than that of said retrieval object with the n th largest instantaneous query score, thereby establishing the n retrieval objects with the largest final query scores.
Claim 5
Dependent Claim
178 words
A method as claimed in claim 1 or 2, for information retrieval under relieved conditions, further comprising: selecting access keys from the inputted query for said accessing the transposed file, based on the values of said given weighting coefficents, the data that relates to the selected access key being copied into main storage; in response to the copying of data from the transposed file into main storage, calculating the instantaneous query score and the maximum anticipated final query score for each retrieval object, based on the contents of the inputted query and the data copied from the transposed file; and stopping the selection of access keys when the retrieval object with the n th largest instantaneous query score has an instantaneous query score larger than the maximum anticipated final query score of each retrieval object having an instantaneous query score less than that of the retrieval object with the n+m th largest instantaneous query score, where m is an integer larger than 2, thereby establishing with sufficient accuracy the n retrieval objects with the largest final query scores.
Claim 6
Dependent Claim
52 words
A method as claimed in claim 3 or claim 4, wherein the access keys include access keys differing in weight depending on the retrieval objects, and wherein the access keys are selected, based on the product of the weight of each access key and said given weighting coefficient of each access key.
Claim 7
Dependent Claim
38 words
A method as claimed in claim 5, wherein for each of said access keys differing in weight depending on the retrieval objects, the retrieval object identifiers are arranged in the transposed file (41) in order of the weight.
References Cited (Backward Citations)
No citation records indexed.
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