JPH07117960B2 - Data retrieval processing method - Google Patents

Description

DETAILED DESCRIPTION [Outline] The present invention relates to a search control method for a database that holds a creation time of data as a key. Even if the time values of the search key and the data key do not match, if the key value is within a predetermined length of time including the specified time, that data is output as the search target data. With this method, it is possible to easily retrieve the necessary data without knowing the exact creation time.

[Industrial application field]

The present invention relates to a database data search control system in an information processing system, and more particularly to a control system for facilitating a database search that holds a data creation time as a key.

For example, for the weather information data collected by an artificial satellite, for example, 6 hours is set as a reference interval, and the data collected at each interval is input to the information processing system. In the information processing system, the data creation time is used as a key. Stored in a weather database so that data can be supplied in response to data retrieval by various processing requests.

[Problems to be solved by conventional technology and invention]

In the case of the meteorological data of the above example, the data creation interval is set to, for example, 6 hours as a reference value, but the creation may be shifted from the reference time by, for example, about 30 minutes, so this data creation Is not prioritized over others to strictly adhere to the creation time. Therefore, the data creation time fluctuates due to various factors.

In the information processing system, when this data is received and stored in the database, the time is read and the time data is processed as a key of the data.

The time value used as this key needs to be an accurate time record with an accuracy of, for example, seconds so that it can be used for various processing applications.

Therefore, in searching, you must know the data creation time and specify a time value that matches the creation time of the specified data as a search key, or specify a period such as from a certain time to a certain time to request a search. I have to.

However, there are many processes that do not require an accurate creation time from the viewpoint of processing, and even in such a process, it is possible to specify the search key value accurately by knowing the data creation time or to specify a complex period. There is a problem that the target data cannot be used unless the search condition is set, which unnecessarily complicates the processing.

[Means for solving problems]

 The figure is a flow chart of the process of the present invention.

The figure shows the flow of search processing of the information processing system.
Is a processing step for receiving a search key input and converting a time value into a predetermined numerical value format, 3 is a processing step for determining both end time values within a predetermined width period from a designated time, and 4 is a search condition based on matching of key values, The processing steps 5 for correcting the specification of the range of key values are the processing steps for data retrieval.

[Action]

In the information processing system, for example, the data search processing program receives a search request similar to the conventional one from the user's program or the like in processing step 1, and a time value is designated as a search key.

In processing step 2, the time value of the input search key is converted into a predetermined time value format as a key value to obtain a search key value.

In processing step 3, a minimum time value obtained by subtracting a predetermined time from the search key value and a maximum time value obtained by increasing the predetermined time are created.

In processing step 4, a search condition modified to search for a key that is equal to or greater than the minimum time value and equal to or less than the maximum time value is generated.

The processing step 5 is the same data search function as the conventional one,
A data search is executed according to the above modified search conditions.

With the above control method, the user of the data does not need to accurately specify the key value of the required data in the search key.For example, by designating only the required reference time, the reference time is set as the target You can search the data created before and after.

〔Example〕

When the present invention is implemented, it is often the case that the data search is performed not by the matching of the key values but by the magnitude comparison. Therefore, it is desirable to make the time value used as the key easy to calculate.

Therefore, for example, the date is represented by the publicly known Mean Julian Day (MJD), which indicates the number of days since January 1, 1900, and the time within one day is represented by a decimal number. For example, a time value with an accuracy of up to seconds is represented as one real value. In this case, the key value in the information processing system is a real number represented by a length of, for example, 64 bits (8 bytes).

By using the time of this expression (hereinafter referred to as MJD time) as the key value, it is possible to compare each key value with one real number subtraction and the positive / negative judgment of the result, and the search process can be performed efficiently. Can be executed.

However, it is difficult for people to understand before the MJD time, so when outputting the key value as a search result or inputting the key value from outside, use the usual year, month, day, hour, minute, second format. It has a conversion function in the information processing system.

In the processing step 1, the data search processing program of the information processing system receives a search request similar to the conventional one from the user's program or the like, and a time value is designated as a search key.

As described above, this time value may be in the format of year, month, day, hour, minute, second, and if necessary, year, month, minute, second, etc. may be omitted.

In processing step 2, the time value in the above format of the input search key is converted into MJD time by a known calculation.

In processing step 3, a minimum time value obtained by subtracting a predetermined time from this MJD time search key value and a maximum time value obtained by increasing the predetermined time are created.

The predetermined values for creating the minimum and maximum time values here are determined by the nature of this data, and in the case of the meteorological data, for example, about 30 minutes (about 0.02 days). Needless to say, different adjustment values may be used for calculating the minimum value and the maximum value, if necessary.

In processing step 4, a search condition modified to search for a key that is greater than or equal to the minimum time value and less than or equal to the maximum time value determined above is generated.

The processing step 5 is the same data search function as the conventional one,
It is a normal one search method according to the modified search conditions. Perform data search by comparing the size of keys.

As a result, the key time value included in the period from the minimum time value to the maximum time value is determined and the data is notified to the search request source as the target data.

According to the control method described above, the user of the data may search the data assuming that the data is always created at the reference time, which facilitates the data search process.

〔The invention's effect〕

As is clear from the above description, according to the present invention, the user of the database in the information processing system does not need to accurately specify the key value of the required data as the search key, and only the value in the vicinity of By designating as if the key value exists, it is possible to retrieve data having a key value in a predetermined range including the designated value, which is a remarkable industrial effect of improving the usability of the system. .

[Brief description of drawings]

 The figure is a flowchart of the process of the present invention. In the figure, 1 to 5 indicate processing steps.

Claims (2)

[Claims] 1. A data search processing method of an information processing system having a database composed of data stored with data creation times discretely generated at any time as a key, wherein the database is searched for a time value in a normal reference time format. Designate as a key, convert the search key to a time value in a predetermined time value format, and add or subtract a predetermined time determined by the character of the data to the converted search key value to set the maximum time value and the minimum time value Then, the data search processing method is characterized in that the search processing of the database is executed according to a search condition having a key that is equal to or more than the set minimum time value and equal to or less than the maximum time value. 2. The data search processing method according to claim 1, wherein an average Julian day is used as the predetermined time value format.