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https://issues.apache.org/jira/browse/CASSANDRA-7396?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15224236#comment-15224236
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Sylvain Lebresne commented on CASSANDRA-7396:
---------------------------------------------
bq. am I correct, that
org.apache.cassandra.db.filter.ColumnFilter.Builder#addSubSelection would be
the "key" method to query individual elements / slices from collections (sets +
maps)?
You are.
But I'll note that for this ticket my preference would be to stick to basically
expose what {{ColumnFilter.Builder#addSubSelection}} basically provides
internally. In particular, I'd rather not add anything for lists as we can't
make dealing with lists efficient. In fact, I'd rather make it clear that lists
are a second class citizen that is rarely useful and only if you know what
you're doing.
I'm also not entirely convinced by the {{?}} syntax suggested above. In
particular, having {{map?\[key\]}} return a boolean but {{map?\[key1...key2\]}}
a set of value is a bit inconsistent. I'm also not sure that syntax is common
enough that it's worth adding specific syntax for it. We could for instance
have {{has(set, key1)}} if we just want to test an element existence. For
{{map?\[key1...key2\]}}, an alternative could be to have a {{keys()}} function
that applied to a map returns the set of keys.
> Allow selecting Map key, List index
> -----------------------------------
>
> Key: CASSANDRA-7396
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7396
> Project: Cassandra
> Issue Type: New Feature
> Components: CQL
> Reporter: Jonathan Ellis
> Assignee: Robert Stupp
> Labels: cql
> Fix For: 3.x
>
> Attachments: 7396_unit_tests.txt
>
>
> Allow "SELECT map['key]" and "SELECT list[index]." (Selecting a UDT subfield
> is already supported.)
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