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https://issues.apache.org/jira/browse/CALCITE-5982?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde resolved CALCITE-5982.
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Fix Version/s: 1.36.0
Resolution: Fixed
Fixed in
[436ae7d|https://github.com/apache/calcite/commit/436ae7d296dfcac321ec461feaf0f645ec980993];
thanks for the PR, [~oliverlee]!
> Allow overloading the created enumerable in Calcite when calling getTables()
> or getColumns()
> ---------------------------------------------------------------------------------------------
>
> Key: CALCITE-5982
> URL: https://issues.apache.org/jira/browse/CALCITE-5982
> Project: Calcite
> Issue Type: New Feature
> Reporter: Oliver Lee
> Assignee: Oliver Lee
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.36.0
>
>
> The goal is to introduce a mechanism that allows overloading the enumerable
> type that is created when {{getTables()}} and {{getColumns()}} is called. If
> a user provides an overloaded {{{}MetaTable{}}}/ {{MetaColumn}} class, then
> they can add in additional metadata fields that they would like to be
> transferred.
>
> Currently, {{CalciteMetaImpl}} in {{getTables()}} and {{getColumns()}} calls
> are hardcoded to do reflection on {{MetaTable.class}} and
> {{MetaColumn.class}} ‘ fields, matched with the list of column names that are
> passed in. Reflection is important here, as it creates the proper
> {{ColumnMetaData}} and {{Signature}} that the client needs to deserialize.
> See here for {{[getTables()|#L270]]}} and here for
> [{{getColumns()}}|https://github.com/apache/calcite/blob/164ff0a27e243850d294908dc5cff90760d0a35a/core/src/main/java/org/apache/calcite/jdbc/CalciteMetaImpl.java#L320]
>
>
> I would like to introduce fields ( {{metaTableClass}} , {{metaColumnClass}} )
> on {{CalciteMetaImpl}} that determine which class to use for each of these.
> This will be configured as a {{CalciteConnectionProperty}} when making the
> {{jdbc:calcite}} connection, and default to MetaTable.class and
> MetaColumn.class if not provided.
>
>
> Requirements:
> * User can specify in {{Properties}} new {{CalciteConnectionProperty}} ’s to
> specify which overloaded class of {{CalciteMetaTable}} and {{MetaColumn}} to
> use
> * If not specified, it will default to {{CalciteMetaTable.class}} and
> {{MetaColumn.class}}
>
>
> The provided overloaded class will create a subclass of {{CalciteMetaTable}}
> / {{MetaColumn}} that has the same shape constructor and also provide an
> override for the function {{{}getColumnNames(){}}}.
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