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https://issues.apache.org/jira/browse/OFBIZ-4346?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13068996#comment-13068996
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David E. Jones commented on OFBIZ-4346:
---------------------------------------
The concern of the attribute is not so much if limit/offset are allowed, if
they are not supported the JDBC driver will eventually throw an exception.
The attribute would be used to configure the SQL syntax variation for the
offset/limit concept. The attribute might look something like:
{code}
<xs:attribute name="offset-style" default="fetch">
<xs:simpleType><xs:restriction base="xs:token">
<xs:enumeration value="fetch"/>
<xs:enumeration value="limit"/>
</xs:restriction></xs:simpleType>
</xs:attribute>
{code}
The code for the SQL syntax options might look like:
{code}
if (databaseNode."@offset-style" == "limit") {
// use the LIMIT/OFFSET style
this.sqlTopLevel.append(" LIMIT ").append(limit ?: "ALL")
this.sqlTopLevel.append(" OFFSET ").append(offset ?: 0)
} else {
// use SQL2008 OFFSET/FETCH style by default
if (offset != null) this.sqlTopLevel.append(" OFFSET
").append(offset).append(" ROWS")
if (limit != null) this.sqlTopLevel.append(" FETCH FIRST
").append(limit).append(" ROWS ONLY")
}
{code}
This is how I would have implemented it in OFBiz, demonstrated by the fact that
this is how I implemented it Moqui.
> Support MySQL and Postgres's LIMIT and OFFSET options
> -----------------------------------------------------
>
> Key: OFBIZ-4346
> URL: https://issues.apache.org/jira/browse/OFBIZ-4346
> Project: OFBiz
> Issue Type: Improvement
> Components: framework
> Affects Versions: SVN trunk
> Reporter: Shi Jinghai
> Priority: Minor
> Attachments: mysql_postgres_limit_offset_trunk.patch
>
>
> Two helper classes are added for MySQL and Postgres to support LIMIT and
> OFFSET options.
> These classes can be configured in entityengine.xml:
> helper-class="org.ofbiz.entity.datasource.postgres.PostgresHelperDAO" for
> Postgres
> and
> helper-class="org.ofbiz.entity.datasource.mysql.MysqlHelperDAO" for MySQL.
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