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https://issues.apache.org/jira/browse/DERBY-481?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rick Hillegas updated DERBY-481:
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Attachment: derby-481-15-aa-renameAndAddDefault.diff
Attaching derby-481-15-aa-renameAndAddDefault.diff. Tests ran cleanly for me.
Committed at subversion revision 712664.
This patch makes two changes, per the spec:
A) Prevents users from renaming columns which are referenced by generation
clauses.
B) Prevents users from using ALTER TABLE to add defaults to generated columns.
Note that the parser already prevents you from adding defaults to generated
columns via CREATE TABLE.
Touches the following files:
M java/engine/org/apache/derby/impl/sql/compile/RenameNode.java
Raises an error if you try to rename a column referenced by a generation clause.
M java/engine/org/apache/derby/impl/sql/compile/ModifyColumnNode.java
Raises an error if you try to add a default to a generated column.
M java/engine/org/apache/derby/loc/messages.xml
M java/shared/org/apache/derby/shared/common/reference/SQLState.java
New error messages for the newly forbidden conditions.
M
java/testing/org/apache/derbyTesting/functionTests/tests/lang/GeneratedColumnsTest.java
New test cases.
> 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,
> 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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