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https://issues.apache.org/jira/browse/DERBY-4681?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13484354#comment-13484354
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Karl San Gabriel commented on DERBY-4681:
-----------------------------------------
Hello Rick,
I looked into the codes and at the stack trace. Based on my investigation, I
would say the application needs to store the table fields that go with any
views during CREATE VIEW.
Currently, the application keeps track of which tables a view uses or which
views depend on a particular table. One fix that I am
inclined to do includes adding a new table field in DEPENDENTFINDER to store
which table-field a view uses during CREATE VIEW and
using that information in processing the ALTER TABLE...DROP COLUMN...RESTRICT
or CASCADE.
select * from sys.sysdepends where DEPENDENTFINDER='View';
==================================================================================================
DEPENDENTID |DEPENDENTFINDER|PROVIDERID
|PROVIDERFINDER
==================================================================================================
437c8055-013a-9605-32d1-000000bf1590|View
|48d7402a-013a-9605-32d1-000000bf1590|ColumnsInTable
--> providerid points to T3 table in systables, no way to know which fields the
view actually uses
437c8055-013a-9605-32d1-000000bf1590|View
|f55fc0a6-013a-7ea4-0336-000000bf1430|ColumnsInTable
--> providerid points to T2 table in systables, no way to know which fields the
view actually uses
The other fix that I am thinking of is to reuse the codes that check if the
fields and tables are valid entities for example during a CREATE VIEW
operation.
Your thoughts?
Thanks,
Karl
> Dropping a column in the table drops the views that use this table
> ------------------------------------------------------------------
>
> Key: DERBY-4681
> URL: https://issues.apache.org/jira/browse/DERBY-4681
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.3.1.4, 10.3.2.1, 10.3.3.0, 10.4.1.3, 10.4.2.0,
> 10.5.1.1, 10.5.2.0, 10.5.3.0, 10.6.1.0
> Environment: Windows 7 Enterprise, JDK SE 1.6 u20
> Reporter: Grzegorz Łyp
> Priority: Critical
> Labels: derby_triage10_8
> Attachments: DERBY-4681-LEADS.txt
>
>
> If i have a table and a view that uses this table, after dropping a column
> from this table the whole view is also dropped.
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