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https://issues.apache.org/jira/browse/JDO-660?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13474765#comment-13474765
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Craig L Russell commented on JDO-660:
-------------------------------------
I've updated chapters 15, 18, and 19 to reflect this change.
The semantics were added to 18.4:
The position attribute specifies the relative position of the column when
generating schema for the table. Columns are defined in the order as specified
by the position attribute, with 0 being the first column defined. Columns with
no position attribute (default, or with a value of -1), are defined at the end
of the table. Columns with the same position attribute are defined together but
with an arbitrary relative position.
> Ability to specify positioning of field 'column(s)' in datastore "table"
> ------------------------------------------------------------------------
>
> Key: JDO-660
> URL: https://issues.apache.org/jira/browse/JDO-660
> Project: JDO
> Issue Type: New Feature
> Components: api, specification, tck
> Reporter: Andy Jefferson
> Assignee: Craig L Russell
> Fix For: JDO 3 maintenance release 1 (3.1)
>
> Attachments: column_position.patch
>
>
> With an RDBMS datastore, when generating the schema, it is desirable to be
> able to specify the positioning of the column(s) of a field in the generated
> table.
> With spreadsheet documents, it is critical to be able to define which column
> number is used for a particular field.
> With other datastores it is also likely desirable.
> To achieve this I propose adding an attribute to the XML <column> called
> "position". Similarly for the @Column annotation.
> This can take integer values with 0-origin.
> Complications :
> 1. how this is handled when we have inheritance. If a root class has
> subclass-table inheritance, then those fields are persisted into the tables
> of all subclasses, and we may want to override the positions for those
> individually - to that end the user can override the metadata of the
> superclass fields.
> 2. anything else ?
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