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https://issues.apache.org/jira/browse/METAMODEL-251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15280296#comment-15280296
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Kasper Sørensen commented on METAMODEL-251:
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Interesting idea. I guess we should really carefully consider if we want the
behaviour to change this way. I always thought that the interface of a Row was
resembling that of a Map, and I would usually not expect my maps to throw
exceptions when keys are not resolved. But I can see your point too, failing
fast is good - as long as we then all agree that this is a real failure... It
depends a lot on how we want/expect the usage of the object to be.
I forget if the Row interface has "containsColumn(...)" and/or
"containsSelectItem(...)" like methods already. Having those would be quite an
important addition as well.
The change would certainly be one that has quite some implifications for end
users, so I would suggest that it would go into the 5.0 branch, if we decide to
do this.
Small remarks on your proposal patch, should we decide to go with the idea:
* I would use IllegalArgumentException instead of MetaModelException and the
use of this should be explicit on the interface declaration and javadoc.
* In the exception message I would make sure we're consistent about using the
word "DataSet" and not "result set" or other aliases.
> MetaModel should fail when accessing a column that is not a select item
> -----------------------------------------------------------------------
>
> Key: METAMODEL-251
> URL: https://issues.apache.org/jira/browse/METAMODEL-251
> Project: Apache MetaModel
> Issue Type: Bug
> Affects Versions: 4.5.2
> Environment: Postgres
> Reporter: Hans Drexler
> Attachments: MetaModel251Sample.java
>
>
> In our software, we create a query with SelectItems for 6 out of the 7
> columns of a postgres data base table. We actually forgot to add the seventh
> column as a SelectItem.
> {code}
> query.select(selectItems)
> .from(someTable)
> {code}
> When consuming the rows returned by this query, the code actually fetches the
> column that was not a select item, using a construct like:
> {code}
> row.getValue(table.getColumnByName('foo'));
> {code}
> This returns null values most of the time. But under stress, the code starts
> to throw exceptions.
> It would be much better if MetaModel throws an exception when the code
> attempts to access a column that is not part of the query (fail fast).
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