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https://issues.apache.org/jira/browse/CALCITE-1515?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15723305#comment-15723305
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Julian Hyde commented on CALCITE-1515:
--------------------------------------
[~anmu], It would be great if you fixed this.
I note that we don't use {{Table}} in the {{RelBuilder}} API so we shouldn't
use {{TableFunction}} either. The {{scan}} function has the overloads
{{scan(String...)}} and {{scan(Iterable<String>)}} (basically, looking up a
table in a catalog based on its fully-qualified name), and so {{functionScan}}
should do something similar. I think the signature should be
{code}
RelBuilder functionScan(
Iterable<String> tableFunctionNames,
Iterable<? extends RexNode> operands);
RexNode cursor(int ordinal);
{code}
The operands will be a mixture of scalar values (mainly literals) and
references to input relations. Since an input relation is not a RexNode, the
caller should use the new {{cursor}} method, which references a particular
relational input (already on the RelBuilder's stack). To illustrate, we will
need a complicated contrived example:
{code}
// Here's the SQL
SELECT *
FROM TABLE("mySchema"."myFunction"(
'abc',
(SELECT * FROM "emp"),
123,
(SELECT * FROM "dept")));
// And here's the equivalent RelBuilder code
RelBuilder builder;
builder.scan("EMP")
.scan("DEPT")
.functionScan(Arrays.asList("mySchema"."myFunction"),
builder.literal("abc"),
builder.cursor(0),
builder.literal(123),
builder.cursor(1));
{code}
The {{cursor}} function will create a {{RexCall}} to the
{{SqlStdOperatorTable.CURSOR}} function.
> Support TableFunctionScan in RelBuilder
> ---------------------------------------
>
> Key: CALCITE-1515
> URL: https://issues.apache.org/jira/browse/CALCITE-1515
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.10.0
> Reporter: Anton Mushin
> Assignee: Julian Hyde
> Priority: Minor
>
> Calcite has a TableFunctionScan, which is a RelNode, takes a function, 0 or
> more RelNode inputs, and 0 or more other arguments.
> RelBuilder does not support TableFunctionScan yet.
> add In RelBuilder TableFunctionScanFactory which will create
> LogicalTableFunctionScan like as for LogicalTableScan and factory for others
> RelNodes [
> [example|https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L125]
> ]
> also adding a functionScan method, analogous to the scan method but for table
> functions.
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