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https://issues.apache.org/jira/browse/IGNITE-16115?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrey Mashenkov updated IGNITE-16115:
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Description:
It is allowed to map an object to a single nullable column, which makes 'null'
values legal in the KeyValue view.
Once the 'null' value is possible there is no way to distinguish, if there is
no row in a table for the given key, or the row exists and the mapped column
contains the 'null' value.
Let's introduce {{NullableValue}} class-wrapper for a value and implement
{{{}getNullable(){}}}, and {{getOrDefault()}} + bulk methods.
{{getNullable()}} is useful for cases, when it's not possible to use a
"default", but creates an additional wrapper.
Also, the KeyValueView.get(key) method behavior should be changed:
* return {{null}} if the table has no row for the key.
* return a non-null value for the key.
* fail with a suggestion to use a getNullable, if a {{null}} value returned
for the key to avoid ambiguity.
was:
It is allowed to map an object to a single nullable column, which makes 'null'
values legal in the KeyValue view.
Once the 'null' value is possible there is no way to distinguish, if there is
no row in a table for the given key, or the row exists and the mapped column
contains the 'null' value.
Let's introduce NullableValue class-wrapper for a value and implement
getNullable, and getOrDefault methods for that purpose.
The first one is useful for cases, when it's not possible to use a "default",
but creates an additional wrapper.
Also, the KeyValueView.get(key) method behavior should be changed:
* return {{null}} if the table has no row for the key.
* return a non-null value for the key.
* fail with a suggestion to use a getNullable, if a {{null}} value returned for
the key to avoid ambiguity.
> Implement getNullable and getOrDefault operations.
> --------------------------------------------------
>
> Key: IGNITE-16115
> URL: https://issues.apache.org/jira/browse/IGNITE-16115
> Project: Ignite
> Issue Type: Improvement
> Reporter: Andrey Mashenkov
> Assignee: Andrey Mashenkov
> Priority: Major
> Labels: ignite-3
> Fix For: 3.0.0-alpha4
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> It is allowed to map an object to a single nullable column, which makes
> 'null' values legal in the KeyValue view.
> Once the 'null' value is possible there is no way to distinguish, if there is
> no row in a table for the given key, or the row exists and the mapped column
> contains the 'null' value.
> Let's introduce {{NullableValue}} class-wrapper for a value and implement
> {{{}getNullable(){}}}, and {{getOrDefault()}} + bulk methods.
> {{getNullable()}} is useful for cases, when it's not possible to use a
> "default", but creates an additional wrapper.
> Also, the KeyValueView.get(key) method behavior should be changed:
> * return {{null}} if the table has no row for the key.
> * return a non-null value for the key.
> * fail with a suggestion to use a getNullable, if a {{null}} value returned
> for the key to avoid ambiguity.
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