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https://issues.apache.org/jira/browse/DERBY-481?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12646973#action_12646973
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Dag H. Wanvik commented on DERBY-481:
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I agree.
Another thing:
What is the correct behavior for this case? Here the generation
expression needs a privilege which gets revoked...
ij(CONNECTION0)> create table t (i int, j int, k int generated always as
(dag.myfunc(j)));
ERROR 42504: User 'KNUT' does not have execute permission on FUNCTION
'DAG'.'MYFUNC'.
ij(CONNECTION0)> set role bar; -- this role has the privilege and is granted to
KNUT earlier
0 rows inserted/updated/deleted
ij(CONNECTION0)> create table t (i int, j int, k int generated always as
(dag.myfunc(j)));
0 rows inserted/updated/deleted
ij(CONNECTION0)> set connection connection1;
ij(CONNECTION1)> revoke bar from knut;
0 rows inserted/updated/deleted
ij(CONNECTION1)> set connection connection0;
ij(CONNECTION0)> insert into t values (1,2,default);
ERROR 42504: User 'KNUT' does not have execute permission on FUNCTION
'DAG'.'MYFUNC'.
Triggers, view and constraints in similar circumstances get dropped; should the
generated column get dropped too?
> 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, 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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