JP2002351797A - System and method for retrieving electronic mail and electronic mail retrieval program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up the time required for the retrieval of a Web mail. SOLUTION: A data base server 5 accumulates mails transmitted/received by a client terminal 1 through a Web page displayed by a Web server 3. An application server 6 extracts a keyword from the mail based on the description system of the mail. An index server 7 creates the index of the mail based on the keyword and associates the index with the mail accumulated in the data base server 5. The index server 7 retrieves the index in accordance with a retrieval condition from the client terminal 1 and specifies the applicable mail. The Web server 3 displays the specified mail on the client terminal 1 through the Internet 2 so that it can be referred to.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic mail search system, an electronic mail search method, and an electronic mail search program.

[0002]

2. Description of the Related Art Conventionally, there has been known an electronic mail system that provides an electronic mail transmission / reception service between client terminals via a Web page presented by a Web server on the Internet. In the electronic mail system, a client terminal, which is a mail transmitting / receiving terminal, can browse / transmit / receive electronic mail using only a Web browser. That is, an HTML (Hyper Text Markup Language) document that can be browsed by a Web browser is transmitted and received between the server and the client terminal.

[0003]

In the above-described conventional e-mail system, when a desired e-mail is browsed from transmitted / received e-mails, the e-mail based on a keyword input by a user on the client terminal side. In this case, a full-text search was performed with the entirety of the header part and the text constituting the search target being searched. For this reason, in the related art, there is a problem that the load of the search increases and the time required for the search also increases.

The present invention has been made in view of the above circumstances, and provides an e-mail search system, an e-mail search method, and an e-mail search program that can speed up the time required for Web mail search. Aim.

[0005]

According to the first aspect of the present invention, there is provided an electronic mail exchanged between client terminals via a Web page presented by a Web server on the Internet. An e-mail search system for searching for e-mail, a storage unit for storing e-mail transmitted and received by the client terminal, and a keyword extraction unit for extracting a keyword from the e-mail based on a description format of the e-mail. An index creation unit that creates an index of the electronic mail based on the keyword extracted by the keyword extraction unit; and a link that associates the index created by the index creation unit with the electronic mail stored in the storage unit. Link information generation that generates information Means for searching an index created by the index creation means based on a search request from the client terminal, and an index searched by the search means based on link information created by the link information creation means. And a search result presenting means for presenting the electronic mail specified by the searching means to the client terminal accessing via the Internet. Features.

Further, according to the invention described in claim 2, according to claim 1,
In the electronic mail search system described above, the keyword extracting unit extracts, as a keyword, a character string described in association with an item name of header information for a header portion constituting the electronic mail, and The creating means creates a header index of the electronic mail based on the keyword extracted from the header portion by the keyword extracting means.

Further, according to the invention described in claim 3, according to claim 2,
In the electronic mail search system described above, the index creation unit creates an item header index of the email based on a keyword extracted from the header part by the keyword extraction unit for each item name of the header information. .

Further, according to the invention described in claim 4, according to claim 1,
4. The electronic mail search system according to any one of claims 1 to 3, wherein the keyword extracting means extracts, as a keyword, a word of a minimum unit constituting the body of the body part constituting the e-mail, and creates the index. The means creates a body index of the electronic mail based on the keywords extracted from the body part by the keyword extracting means.

In order to solve the above-mentioned problems,
According to the fifth aspect of the present invention, there is provided an electronic mail search method for searching for an electronic mail transmitted and received between client terminals via a Web page presented by a Web server on the Internet, wherein the electronic mail transmitted and received by the client terminal is provided. Is stored, and a keyword is extracted from the e-mail based on the description format of the e-mail, an index of the e-mail is created based on the keyword, and the index and the stored e-mail are compared. Link information to be associated is generated, the index is searched based on a search request from the client terminal, and an e-mail associated with the index is specified based on the link information.

Further, according to the invention described in claim 6, according to claim 5,
In the electronic mail search method described above, the electronic mail associated with the index is presented to a client terminal accessing via the Internet.

Further, according to the invention described in claim 7, according to claim 5,
Alternatively, in the electronic mail search method according to 6, for the header part constituting the electronic mail, a character string described in association with the item name of the header information is extracted as a keyword, and the character string extracted from the header part is extracted. And generating a header index of the electronic mail based on the keyword.

According to the invention described in claim 8, according to claim 7,
In the electronic mail search method described above, for each item name of the header information, an item header index of the electronic mail is created based on a keyword extracted from the header portion by the keyword extracting means.

According to the ninth aspect of the present invention, the fifth aspect of the present invention provides
In the e-mail search method according to any one of the above items (1) to (8), for a body part constituting the e-mail, a minimum unit word constituting the body is extracted as a keyword, and the keyword extracted from the body part is extracted as a keyword. A text index of the electronic mail is created based on the electronic mail.

In order to solve the above-mentioned problems,
According to the tenth aspect, the Web on the Internet
Accumulating an e-mail sent and received by the client terminal via a web page presented by the server; extracting a keyword from the e-mail based on a description format of the e-mail; and Creating an index of the email, generating link information that associates the index with the stored email, searching the index based on a search request from the client terminal, Specifying an e-mail associated with the index based on the link information.

According to an eleventh aspect of the present invention, in the electronic mail search program according to the tenth aspect, the electronic mail associated with the index is presented to the client terminal accessing through the Internet. The steps are executed by a computer.

According to a twelfth aspect of the present invention, in the electronic mail search program according to the tenth or eleventh aspect, a header portion constituting the electronic mail is
The computer executes a step of extracting a character string described in association with an item name of the header information as a keyword, and a step of creating a header index of the electronic mail based on the keyword extracted from the header part. It is characterized by making it.

According to a thirteenth aspect of the present invention, in the electronic mail search program according to the twelfth aspect, for each item name of the header information, the item of the e-mail is determined based on a keyword extracted from the header part. The method is characterized by causing a computer to execute a step of creating a header index.

According to a fourteenth aspect of the present invention, in the electronic mail search program according to any one of the tenth to thirteenth aspects, the text unit constituting the electronic mail is replaced with a minimum unit constituting the text. The method is characterized by causing a computer to execute a step of extracting a word as a keyword and a step of creating a body index of the electronic mail based on the keyword extracted from the body part.

According to the present invention, a Web provided by a Web server on the Internet by a client terminal
The electronic mail transmitted / received via the page is stored in the storage unit. At this time, a keyword is extracted from the e-mail based on the description format of the e-mail by the keyword extraction unit, and an index of the e-mail is extracted by the index creation unit based on the keyword extracted by the keyword extraction unit. Create Also, link information for associating the index created by the index creating means with the electronic mail stored in the storage means is generated by the link information generating means. When there is a search request from the client terminal, the search unit searches the index created by the index creation unit, and the search result presenting unit searches the index based on the link information generated by the link information generation unit. The electronic mail associated with the index searched by the means is presented to the client terminal accessing through the Internet. Therefore, since it is only necessary to search the index, it is possible to speed up the time required for searching the Web mail as compared with the case of searching the entire text.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. A. Configuration of Embodiment FIG. 1 is a block diagram showing a configuration of an electronic mail system according to an embodiment of the present invention. In FIG. 1, a client terminal 1 has a communication function of connecting to the Internet 2 and accessing a Web server 3 on the Internet 2 and a Web browser (software) for browsing a Web page provided by the Web server 3. It has.

[0021] The Web server 3 transmits a Web page described in accordance with HTML to the client terminal 1 that has accessed via the Internet 2. The Web
The Web page provided by the server 3 includes a Web page for sending and receiving mail between client terminals,
There is a search Web page for browsing a desired e-mail from the transmitted / received e-mails of the user.

The mail server 4 has a Web server 3
It has a function of transferring a mail transmitted from the client terminal 1 from page b to a mail server (not shown) of the destination via the Internet 2 according to the mail address of the destination. In addition, the mail server 4 receives mail transmitted from another client terminal (not shown) to the user via the Internet 2 and stores the mail in a mailbox prepared for each user.

The database server 5 is a mail server 4
In addition to storing mail transmitted and received by the user, data unique to the user (such as authentication information and personal information) is stored. The database server 5 retrieves the stored mail and supplies it to the application server 6 in response to a request from the application server 6 described later.

Here, the index creation will be described in detail. Here, FIG. 2 is a schematic diagram showing the structure of a general mail. As shown in FIG. 2, the mail includes a header part, a body part, and an attached file part (not shown). In the header portion, header information regarding a transmission source, a transmission destination, a transmission time, a mail server, and the like is described.
The header information is described for each item name preset as a mail format.

FIGS. 3 and 4 are conceptual diagrams for explaining the item names of the header information described in the header portion of the mail and their meanings. The character strings preset as the item names of the header information are shown in FIGS.
, “To”, “Cc”, “Bcc”, “S”
object, "Received,""Messa
"ge-id", "From", "Date", "Rep"
ly-To "," In-Reply-To "," Err
ors-To "," Sender "," MIME-Ve "
rsion, "Content-Type", "X-
Mailer ". Note that the header information described here is an example, and the present invention is not limited to this.

"To" indicates the destination (address) of the mail. “Cc” indicates the transmission destination of the mail when the carbon copy is designated. “Bcc” indicates the transmission destination of the mail when the blind copy is specified. "Subject
"t" indicates the title of the mail. "Receive
"d" indicates a record of relaying until the mail is received.
“Message-id” indicates the identification code number assigned to the mail. “From” indicates the mail address of the sender who is the sender in the case of normal outgoing mail, and the mail address of the sender who is the sender in the case of the received mail. “Date” indicates the date and time when the mail was transmitted. “Reply-To” indicates a mail address for reply. “In-Reply-To” indicates a header that records the ID of the original mail when replying to the received mail. “Errors-To” indicates a mail address to which an error message is sent when an error occurs. “Sender” indicates the mail address of the sender assigned by the delivery system. "MIME-Versio
“n” indicates whether the body of the mail is composed of only text or data such as an image or sound is attached. "Co
“nent-Type” indicates the type of the contents of the mail. “X-Mailer” indicates the type and version of the mail software.

Following the header part, there is a body part described by the user. The header part and the body part are separated by “line feed”. In some cases, an attached file converted into a text format is described in the body part.

According to the item name of the header information, the application server 6 converts the mail header stored in the database server 5 into a character string “From” indicating the destination written in “To” from “Head”. For example, a character string indicating a transmission source described in the corresponding field, a character string indicating a title described for “Subject”, and the like are extracted as keywords, and the keywords are supplied to the index server 7. Further, the application server 6 extracts words of the minimum unit as keywords from the body part and the attached file part of the mail stored in the database server 5 by using morphological analysis. Further, the application server 6 generates a Web page by converting the processing result and the search result by indexing into HTML, and supplies the Web page 4 to the Web page.

The index server 7 creates a header index from the header part of the mail stored in the database server 5 according to the keyword extracted from the header part of the mail. As shown in FIG. 5, the header index includes an index file created for each item name of the header information. In the illustrated example, a To index file 10-1 corresponding to the character string “To” indicating the transmission destination, a From index file 10-2 corresponding to the character string “From” indicating the transmission source, and a character string “Subject” indicating the title Subject corresponding to "
A t-index file 10-3 has been created.

The index server 7 creates a body index from the body part and the attached file part of the mail stored in the database server 5 according to the keywords extracted from the body part and the attached file part of the mail. As shown in FIG. 5, the text index includes a text index file 11 created from the text portion and an attached file index file 12 created from the attached file portion (text).

As described above, in the present embodiment, the application server 6 and the index server 7 create an index for each of the header portion and the body portion constituting the mail, and further, for the header portion, An index is created for each set character string.

FIG. 6 is a conceptual diagram showing an example of the contents of each index file described above. In the To index file 10-1, the mail address of the transmission destination described for the character string “To” is used as a keyword, and for each index created according to the keyword, a mail describing the mail address is associated. Have been. For example, as the transmission destination, the mail address “ich
iro @ aaa. co. The mail with “jp” is mail A and mail D. Similarly, for example, the mail address “tarou@aaa.co.j”
The mail with "p" is mail B. Each index and the mail corresponding to the index are linked by associating the mail address (for example, file name, URL, etc.) in the database server 5 with the index.

Also, the From index file 10
-2, the mail address of the transmission source written in the character string "From" is used as a keyword, and a mail in which the mail address is written is associated with each index created according to the keyword. For example,
As the sender, the e-mail address "ichiro @ aa"
a. co. The mail with “jp” is mail A and mail D. Similarly, for example, a mail in which a mail address “tarou@aaa.co.jp” is described indicates that the mail is a mail B.

Subject index file 10
-3 is associated with a mail whose word is used as a title for each index created according to a keyword extracted as a minimum unit word from the title of the mail. For example, mails in which the word “example” is used in the title indicate mail A and mail D. Similarly, for example, a mail in which the word “plan” is described indicates that the mail is the mail B.

In the body index file 11, for each index created according to a keyword extracted as a minimum unit word from the body of the mail, a mail whose word is used in the body is associated. For example, it indicates that the mails in which the word “Hello!” Is used in the body are mails A, B, and D. Similarly, for example, the mail in which the word “Taro” is used in the text indicates mails A to F.

B. Next, the operation of the present embodiment will be described in detail with reference to the flowcharts shown in FIGS. B-1. Index creation First, the client terminal 1 uses a Web browser,
The user accesses the Web server 3 via the Internet 2 to browse / transmit / receive e-mails (step S1).
Web server 3 that received a request to view and send / receive mail
Requests the application server 6 to view / transmit / receive the mail (step S2). The application server 6 issues an instruction to the inquiry destination server according to the type of request. For example, in the case of a mail transmission request, it instructs the mail server 4 to transmit mail. If it is a request to read the mail, the database server 5 is instructed to read the mail. If the request is a mail reception request, the mail server 4 instructs the mail server 4 to receive the mail and instructs the database server 5 to store the mail (step S3).

After the transmission and reception of the mail, the mail is stored in the database server 5 (step S).
4). Next, an index is created from the mail stored in the database server 5 by the index server 7, the index is converted into a database, stored in the index server 7, and supplied to the Web server 4 via the application server 6. (Step S5).

More specifically, according to the item name of the header information, the application server 6 extracts a character string indicating the destination, a character string indicating the source, from the header portion of the mail stored in the database server 5. A character string indicating a title or the like is extracted as a keyword, and the keyword is supplied to the index server 7. The index server 7 creates a header index from the header part of the mail stored in the database server 5 according to the keyword extracted from the header part of the mail. The header index file is stored in the index server 7.

The application server 6 extracts words in the minimum unit as keywords from the body part and the attached file part of the mail stored in the database server 5 by using morphological analysis. The index server 7 creates a text index from the text part and the attached file part of the mail stored in the database server 5 according to the keywords extracted from the text part and the attached file part of the mail. The body index file is stored in the index server 7.

Returning to FIG. 7, the application server 6 generates a Web page by converting the processing result by indexing into HTML, and supplies it to the Web server 3 (step S6). Then, the Web server 3 uses the HTM
The L-processed result is transmitted to the client terminal 1 via the Internet 2 as a Web page (step S7).

B-2. Search The user accesses the Web server 3 via the Internet 2 by using the client terminal 1, and searches for a mail using a Web browser (step S10).
More specifically, when there is a search request from the client terminal 1, the Web server 4 transmits a search screen 20 as shown in FIG. The search screen 20 includes a search destination box 21 for specifying which part of the mail is to be searched, a keyword box 22 for specifying a keyword, a condition box 23 for inputting a condition, and a search operation. A "search" button 24 for instructing, a "next search" button 25 for proceeding to the next search, and a "cancel" button 26 for canceling the search are displayed. In the search destination box 21, items (transmission source, transmission destination, title) and text used in the header portion of the mail can be selected from the pull-down menu as the search target. The source corresponds to “From” in the header, and the destination is “T”.
o ", and the title corresponds to" Subject ". In the keyword box 22, a desired character string is input by the user. In the condition box 23, “and (AND: logical product)”,
"Or (OR: logical sum)" can be selected from a pull-down menu.

The user selects a search destination from the search screen 20,
After entering keywords and conditions, "Search" button 2
4 Click Thereby, the Web server 4 requests the application server 6 to search for the mail (step S11). The application server 6 supplies the search destination, the keyword and the condition to the index server 7 and makes an inquiry (step S).
12). On the other hand, the index server 7 searches the index in the database and supplies the search result to the application server 6 (step S1).
3).

More specifically, the index server 7 specifies an index file to be searched according to a search destination specified by the user, and searches the specified index file by a keyword specified by the user. For example, when the user searches for “source” as a search destination and “panda@dddd.co.
jp ”(see FIG. 9), the index server 7 uses the keyword“ panda@dddd.co.jp ”as a keyword to set the From index file 10
Search for -2. As a result, the index server 7
In the example shown in FIG. 6, mails A and F are obtained.

Next, the index server 7 designates “transmission destination” as a search destination and “ichiro@aaa.co.jp” as a keyword (FIG. 9).
) According to “ichiro@aaa.co.j
To index file 1
Search for 0-1. As a result, the index server 7
Acquires mails A and D in the example shown in FIG.

Next, the index server 7 specifies the “example title” according to the “title” as the search destination and the “example case” as the keyword (see FIG. 9) specified by the user.
Is used as a keyword to search the Subject index file 10-3. As a result, in the example shown in FIG. 6, the index server 7 sends the mails A and D (“example”,
Mail including all of "" and "").

Further, the index server 7 searches the text index file 11 using “today” as a keyword according to “text” as a search destination and “today” as a keyword (see FIG. 9) specified by the user. . As a result, in the example shown in FIG. 6, the index server 7 acquires the mails A and F.

Next, the index server 7 narrows down the search results according to the conditions specified by the user. In the example of FIG. 9, “pan” is set in “Source (From)”.
da @ ddd. co. jp ", and" and "and" destination (To) "are" ichiro@aaa.co.j ".
p "," or "," Title (Subject
“t)” includes “example”, and a condition is specified to search for an email that includes “or” and “body” includes “today”. Therefore, as shown in FIG. 9, the index server 7 determines that the mail A is the final one among the mails A and F, the mails A and D, the mails A and D, and the mails A and F as shown in FIG. Get as search result.

Returning to FIG. 6, the application server 6 displays a screen for displaying the search result by the HTM
It is generated in the L format and supplied to the Web server 4 (Step S14). The Web server 4 transmits the HTML search result screen to the client terminal 1 via the Internet 2 (Step S15). This allows
In the client terminal 1, a search result screen including the contents of the mail A is displayed by the Web browser in the above example.

[0049]

As described above, according to the present invention,
An e-mail transmitted / received by a client terminal via a Web page provided by a Web server on the Internet is stored in a storage unit. At this time, the e-mail is extracted by a keyword extraction unit based on the description format of the e-mail. A keyword is extracted from the e-mail based on the keyword extracted by the keyword extracting unit, and an index created by the index creating unit is created by the link information generating unit. Link information for associating with the e-mail stored in the storage means is generated, and when a search request is issued from the client terminal, the search means searches the index created by the index creation means, and the link information Generation means Based on the generated link information, an e-mail associated with the index searched by the search unit is specified, and the search result presentation unit specifies the client terminal accessing through the Internet. Since the e-mail is presented, it is only necessary to search the index, so that the time required for searching the Web mail can be shortened as compared with the case of searching the entire text.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic mail system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a general mail.

FIG. 3 is a conceptual diagram for explaining item names of header information described in a header portion of a mail and their meanings.

FIG. 4 is a conceptual diagram for explaining an item name of header information described in a header portion of a mail and its meaning.

FIG. 5 is a conceptual diagram showing an example of creating an index file in an index server.

FIG. 6 is a conceptual diagram showing an example of the contents of each index file.

FIG. 7 is a flowchart for explaining the operation of the present embodiment.

FIG. 8 is a flowchart for explaining the operation of the present embodiment.

FIG. 9 is a schematic diagram illustrating an example of a search screen provided by a Web server.

[Explanation of symbols]

Reference Signs List 1 client terminal 2 Internet 3 Web server (search result presentation means) 4 mail server 5 database server (storage means) 6 application server (keyword extraction means) 7 index server (index creation means, link information generation means, search means) 10- 1 To index file 10-2 From index file 10-3 Subject index file 11 Body index file 12 Attached file index file

Continuing on the front page (72) Inventor Takao Matsumoto 2-2-2 Otemachi, Chiyoda-ku, Tokyo Urbannet Otemachi Building Inside NTMI Corporation (72) Inventor Katsuya Yamashita Otemachi, Chiyoda-ku, Tokyo 2-2-2 Urbannet Otemachi Building Inside NTMI Corporation (72) Inventor Hiroyasu Yuzawa 2-2-2 Otemachi, Chiyoda-ku, Tokyo NTT Urban Corporation Otemachi Building・ T-ME F-term (reference) 5B075 KK07 KK13 KK33 KK39 ND03 ND23 ND36 NK02 NK13 NK24 NK31 PQ05 UU24 5K030 GA01 HA08 HC01 HD05 JT03 KA01 KA06 KA13 LD11 MB18

Claims (14)

[Claims] 1. An electronic mail search system for searching for an electronic mail transmitted and received between client terminals via a Web page presented by a Web server on the Internet, wherein the electronic mail is transmitted and received by the client terminal. Accumulating means, keyword extracting means for extracting a keyword from the e-mail based on the description format of the e-mail, and index for creating an index of the e-mail based on the keyword extracted by the keyword extracting means Creating means, link information generating means for generating link information for associating the index created by the index creating means with the electronic mail stored in the storage means, based on a search request from the client terminal, Index A search unit that searches an index created by the search unit, and identifies an email associated with the index searched by the search unit based on the link information generated by the link information generation unit; A search result presenting means for presenting the electronic mail specified by the searching means to the client terminal accessed via the Internet. 2. The method according to claim 1, wherein the keyword extracting unit extracts, as a keyword, a character string described in association with an item name of the header information, for a header part constituting the electronic mail. 2. The electronic mail search system according to claim 1, wherein a header index of the electronic mail is created based on the keyword extracted from the header portion by the keyword extracting unit. 3. The index creation unit creates an item header index of the electronic mail for each item name of the header information based on a keyword extracted from the header part by the keyword extraction unit. Email search system as described. 4. The keyword extracting means extracts, as a keyword, a word of a minimum unit constituting a text from a text part constituting the e-mail, and the index creating means outputs the keyword by the keyword extracting means. 4. The e-mail search system according to claim 1, wherein a main body index of the e-mail is created based on a keyword extracted from the main body part. 5. An e-mail search method for searching for e-mail transmitted and received between client terminals via a Web page presented by a Web server on the Internet, wherein the method stores e-mail transmitted and received by the client terminals. Extracting a keyword from the email based on a description format of the email; creating an index of the email based on the keyword; link information for associating the index with the stored email. And searching the index based on a search request from the client terminal, and identifying an email associated with the index based on the link information. 6. The electronic mail search method according to claim 5, wherein the electronic mail associated with the index is presented to a client terminal accessed via the Internet. 7. For a header portion constituting the electronic mail, a character string described in association with an item name of header information is extracted as a keyword, and based on the keyword extracted from the header portion. ,
7. The electronic mail search method according to claim 5, wherein a header index of the electronic mail is created. 8. The method according to claim 7, wherein an item header index of the electronic mail is created for each item name of the header information based on a keyword extracted from the header portion by the keyword extracting means. E-mail search method. 9. A text index of the electronic mail based on the keyword extracted from the text part of the text part constituting the electronic mail based on the keyword extracted from the text part. 9. An electronic mail search method according to claim 5, wherein the electronic mail search method comprises: 10. A step of storing an e-mail transmitted / received by a client terminal via a Web page presented by a Web server on the Internet, and extracting a keyword from the e-mail based on a description format of the e-mail. Creating an index of the email based on the keyword; generating link information for associating the index with the stored email; and responding to a search request from the client terminal. Searching for the index based on the link information, and identifying an email associated with the index based on the link information. 11. The method according to claim 10, further comprising the step of causing the computer to execute a step of presenting the electronic mail associated with the index to the client terminal accessing via the Internet.
The described e-mail search program. 12. Extracting a character string described in association with an item name of the header information as a keyword for a header part constituting the electronic mail; On the basis of,
12. The computer-readable storage medium according to claim 10, further comprising: causing a computer to execute the step of creating a header index of the electronic mail. 13. The method according to claim 1, further comprising: causing a computer to execute a step of creating an item header index of the e-mail based on a keyword extracted from the header part for each item name of the header information.
2. The e-mail search program according to 2. 14. A step of extracting a word of a minimum unit constituting a body as a keyword for a body part constituting the e-mail, and a step of extracting the word of the e-mail based on the keyword extracted from the body part. Generating a text index.
14. The electronic mail search program according to any one of 0 to 13.