[jira] [Comment Edited] (ARROW-6536) [C++] CSV reader accept schema

["Joris Van den Bossche (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARROW-6536?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17025031#comment-17025031 ] 

Joris Van den Bossche edited comment on ARROW-6536 at 1/28/20 10:47 AM:
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The use case mentioned in ARROW-7655 (allow to specify the nullability of fields by specifying a full schema) might be an argument for having a _separate_ {{schema}} option where you specify the _exact_ schema that the output should have (while with {{column_types}} isn't strict on the exact columns being specified).


was (Author: jorisvandenbossche):
The use case mentioned in ARROW-7655 (allow to specify the nullability of fields by specifying a full schema) might be an argument for having a _separate_ {{schema}} option where you specify the _exact_ schema that the output should have.

> [C++] CSV reader accept schema
> ------------------------------
>
>                 Key: ARROW-6536
>                 URL: https://issues.apache.org/jira/browse/ARROW-6536
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: C++, C++ - Dataset
>            Reporter: Neal Richardson
>            Priority: Major
>              Labels: csv, dataset
>
> The CSV reader lets you specify {{column_types}}, but this is an {{unordered_map}} of column name and type. Why not accept a Schema instead? Isn't that essentially an ordered map? Seems that if you took a Schema, some of the validation of what's being passed in would already have been handled. Plus, I suspect that the Datasets project will want to do even more with passing a Schema (e.g. selecting a subset of columns). 
> Thoughts [~pitrou] [~fsaintjacques] [~bkietz]?



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