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https://issues.apache.org/jira/browse/DERBY-481?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12650238#action_12650238
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Dag H. Wanvik commented on DERBY-481:
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Thanks for your incorporating the comments, Rick!
Reviewed derby-481-08-aa-castToDeclaredType.diff
Patch looks good!
Some small notes on the test: I compared with the
table found in the refman under the CAST function
(http://db.apache.org/derby/docs/dev/ref/rrefsqlj33562.html) to check
that all conversions are included.
- smallint, int, bigint and decimal lacks a testcase for char
- char lacks testcases for smallint, int, bigint and decimal
- the varchar test seems wrong (identical to the char case; copy/paste
error?)
- the three bitdata cases lack cases for clob and blob
- timestamp lacks cases for date and time
- xml is omitted
Some of the omissions may be intentional (xml), if so it would be good
to indicate why they are omitted in this test.
> implement SQL generated columns
> -------------------------------
>
> Key: DERBY-481
> URL: https://issues.apache.org/jira/browse/DERBY-481
> Project: Derby
> Issue Type: New Feature
> Components: SQL
> Affects Versions: 10.0.2.1
> Reporter: Rick Hillegas
> Assignee: Rick Hillegas
> Attachments: derby-481-00-aa-prototype.diff,
> derby-481-01-aa-catalog.diff, derby-481-02-aa-utilities.diff,
> derby-481-03-aa-grammar.diff, derby-481-04-aa-insert.diff,
> derby-481-05-aa-update.diff, derby-481-06-aa-genreferences.diff,
> derby-481-07-aa-noSQLinRoutines.diff, derby-481-07-ab-noSQLinRoutines.diff,
> derby-481-08-aa-castToDeclaredType.diff, derby-481-09-aa-dummyDefaults.diff,
> derby-481-10-aa-foreignKeyActions.diff, derby-481-11-aa-notNull.diff,
> derby-481-12-aa-padding.diff, derby-481-13-aa-alterDatatype.diff,
> derby-481-14-ab-dropColumn.diff, derby-481-15-aa-renameAndAddDefault.diff,
> derby-481-16-aa-dropFunction.diff, derby-481-17-aa-currentSchema.diff,
> derby-481-18-aa-updatableResultSets.diff, derby-481-19-aa-cleanup.diff,
> GeneratedColumns.html, GeneratedColumns.html, GeneratedColumns.html
>
>
> Satheesh has pointed out that generated columns, a SQL 2003 feature, would
> satisfy the performance requirements of Expression Indexes (bug 455).
> Generated columns may not be as elegant as Expression Indexes, but they are
> easier to implement. We would allow the following new kind of column
> definition in CREATE TABLE and ALTER TABLE statements:
> columnName GENERATED ALWAYS AS ( expression )
> If expression were an indexableExpression (as defined in bug 455), then we
> could create indexes on it. There is no work for the optimizer to do here.
> The Language merely has to compute the generated column at INSERT/UPDATE time.
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