Part 17: Database crawl
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In this article, I will introduce how to crawl and search the data stored in the database.
When retrieving data from a database with SQL, if you want to search under conditions that require linguistic processing, you can use Fess to efficiently search the data in the database. In addition, Fess can crawl and search for any database for which a JDBC driver is provided.
Database settings
This time I will introduce MySQL database crawl as an example. Prepare a MySQL server with the following settings.
| item | value |
|---|---|
| url | mysql://localhost:3306 |
| Database name | testdb |
| username | hoge |
| password | fuga |
Also, prepare the following table in testdb.
CREATE TABLE doc (
id BIGINT NOT NULL AUTO_INCREMENT,
title VARCHAR(100) NOT NULL,
content VARCHAR(255) NOT NULL
PRIMARY KEY (id)
);
Enter data in the table as follows.
INSERT INTO doc (title, content) VALUES ('title 1', 'contents 1 ');
INSERT INTO doc (title, content) VALUES ('title 2', 'contents 2 ');
INSERT INTO doc (title, content) VALUES ('title 3', 'contents 3 ');
INSERT INTO doc (title, content) VALUES ('title 4', 'contents 4 ');
INSERT INTO doc (title, content) VALUES ('title 5', 'contents 5 ');
Build Fess
Next, build Fess. This time I will use Fess-13.3.2. You can get the Fess ZIP file from the download page.
JDBC driver installation
After starting Fess, press “Install” in “System in Management Screen”> “Plugins” to display the plugin installation screen. Select “mysql-connector-java-8.0.17” on the remote tab and click “Install” to install the MySQL JDBC driver.
If you want to install one that is not listed, upload the file from the local tab and install it.
Crawl settings
From here, I will explain the setting of MySQL database crawl.
Log in to Fess management screen, and then to New “crawl”> “data store”. Set the following four items on the setting screen.
name
Handler name
The parameter
script
Please enter any string in the name. Set the handler name to “DataBaseDataStore”.
This parameter is in accordance with the contents of the database, is set as follows.
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=UTF-8
username=hoge
password=fuga
sql=select * from doc
Parameter has become a “key = value” format. The explanation of the key is as follows.
| Key | value |
|---|---|
| driver | Driver class name |
| url | Database server URL |
| username | Username for connecting to the database |
| password | Password to connect to the database |
| sql | SQL statement to get the crawling target |
Set the script as follows.
url="http://localhost/" + id
host="localhost"
site="localhost"
title=title
content=content
cache=content
digest=content
anchor=
content_length=content.length()
last_modified=new java.util.Date()
Script also has become the same as the parameter “key = value” format. A description of each key is as follows.
| Key | value |
|---|---|
| url | URL (link to be displayed on the search results) |
| host | hostname |
| site | Site pass |
| title | title |
| content | Document content of the (index target string) |
| cache | Document of cache (not indexed) |
| digest | Digest part displayed in search results |
| anchor | Links included in the document (usually not required) |
| content_length | Document length |
| last_modified | Last updated date of the document |
The value is treated as Groovy. Close the string with double quotes. You can use the database column name as a variable.
The value you specify will be indexed for searching, so specify it according to your requirements.
Start Crawl/Perform Search
After registering the crawl settings, click “Start Now” from “System”> “Scheduler”> “Default Crawler”. Wait for a while until the crawl is complete.
After the crawl is complete, go to “http://localhost:8080/” and search. You should see the following search results.
This time, I explained how to crawl Fess database. Fess can crawl databases other than MySQL with the same settings as long as it has a JDBC driver. Please, try it.