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https://issues.apache.org/jira/browse/CALCITE-3379?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16948284#comment-16948284
 ] 

Wang Yanlin commented on CALCITE-3379:
--------------------------------------

it's *trims* not *trim*.
Trim is valid, but trims is invalid.
Or, just check using a *invalid_function* call like this

{noformat}
final String create = "create table t1 (\n"
          + " h varchar(3) not null,\n"
          + " i varchar(3),\n"
          + " j int not null as (char_length(h)) virtual,\n"
          + " k varchar(3) null as (invalid_function(i)) virtual)";
      boolean b = s.execute(create);
      assertThat(b, is(false));

      int x = s.executeUpdate("insert into t1 (h, i) values ('abc', 'de ')");
      assertThat(x, is(1));
{noformat}

 

> Support expand STRING column expression in table during sql-to-rel conversion
> -----------------------------------------------------------------------------
>
>                 Key: CALCITE-3379
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3379
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.21.0
>            Reporter: Danny Chen
>            Assignee: Danny Chen
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.22.0
>
>          Time Spent: 2h
>  Remaining Estimate: 0h
>
> Now there are 2 ways to convert a RelOptTable to LogicalTableScan:
> 1. One way is to open the Config#isConvertTableAccess[1] flag and the 
> SqlToRelConverter would invoke the #toRel method which transforms the table 
> to a node returned by the user(Usually a table scan).
> 2. Another way is to use the LogicalTableScan rule, this rule would invoke 
> RelOptTable#toRel and wrap the returned node with a LogicalTableScan.
>  
> The difference between 1 and 2 is that, 2 happens in the planning rule but 1 
> happens in sql-to-rel conversion, 1 also supports to expand the table columns 
> based on the defined default values expressions, see 
> InitializerExpressionFactory#newColumnDefaultValue.
>  
> The problem with the InitializerExpressionFactory#newColumnDefaultValue is 
> that it uses InitializerContext#convertExpression to convert a SqlNode, but 
> if the SqlNode is not validated, we always got a RexCall with 
> SqlUnresolvedFunction. We should give the user chance to validate their 
> SqlNode or even we can support pure string expressions which can be used to 
> persist.
>  
> Another problem with #toRel is that after the expressions applied as a 
> projection, user has no chance to apply any other relational nodes if they 
> want, we can actually support this, the same way as we support the column 
> expressions.
>  
> [1]https://github.com/apache/calcite/blob/2dc97e6723e1b5bf762540f87ffffb5cd1a848a1/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java#L5605



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