问题
We have the following two tables in our mySQL:
mysql> describe comment;
+--------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+--------------+------+-----+---------+-------+
| id | int(11) | YES | | NULL | |
| blogpost_id | int(11) | YES | | NULL | |
| comment_text | varchar(256) | YES | | NULL | |
+--------------+--------------+------+-----+---------+-------+
mysql> describe comment_tags;
+------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+-------------+------+-----+---------+-------+
| comment_id | int(11) | YES | | NULL | |
| tag | varchar(80) | YES | | NULL | |
+------------+-------------+------+-----+---------+-------+
Where each comment can have multiple tags. We can import the entire comment into Solr using the Data Import Handler. However I am not sure how to import the tags for each comment into a multivalued field defined the schema.xml for each comment document.
Please advise. Thanks
回答1:
Try something like this:
<dataConfig>
<!-- dataSource is just an example. Included just for completeness. -->
<dataSource batchSize="500" type="JdbcDataSource" driver="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost/my-database" user="root" password="somethinglong1283"/>
<document>
<entity name="comment" pk="id" query="SELECT * FROM comment">
<field column="blogpost_id" name="blogpost_id"/>
<field column="comment_text" name="comment_text" />
<entity name="comment_tags" pk="comment_id" query="SELECT * FROM comment_tags WHERE comment_id='${comment.id}'">
<field column="tag" name="tag" />
</entity>
</entity>
</document>
回答2:
You can also use GROUP_CONCAT with a Seperator(e.g " , ") and then try something like this :
<dataConfig>
<!-- dataSource is just an example. Included just for completeness. -->
<dataSource type="JdbcDataSource" driver="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost/db" user="root" password="root"/>
<document>
<entity name="comment" pk="id" query="SELECT *, group_concat(tags) as comment_tags FROM comment" transformer="RegexTransformer">
<field column="blogpost_id" name="blogpost_id"/>
<field column="comment_text" name="comment_text" />
<field column="tag" name="comment_tags" splitBy = "," />
</entity>
</document>
</dataConfig>
It'll increase the Performance and also will remove the Dependency of another query.
回答3:
If other solution not work then try this one.
<dataConfig>
<!-- dataSource is just an example. Included just for completeness. -->
<dataSource type="JdbcDataSource" driver="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost/db" user="root" password="root"/>
<document>
<entity name="comment" pk="id" query="SELECT *, group_concat(tags) as tag FROM comment" transformer="RegexTransformer">
<field column="blogpost_id" name="blogpost_id"/>
<field column="comment_text" name="comment_text" />
<field column="tag" splitBy="," sourceColName="tag"/>
</entity>
</document>
</dataConfig>
Add field in schema.xml
<field name="tag" type="string" indexed="true" stored="true" multiValued="true"/>
If you want to use custom separator in mysql then use below one.
GROUP_CONCAT(tags SEPARATOR '~,~') AS tags
If you want to DISTINCT
in concat tag then
GROUP_CONCAT(DISTINCT tags SEPARATOR '~,~') AS tags
来源:https://stackoverflow.com/questions/20233837/importing-multi-valued-field-into-solr-from-mysql-using-solr-data-import-handler