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https://issues.apache.org/jira/browse/DERBY-6362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13797198#comment-13797198
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Knut Anders Hatlen commented on DERBY-6362:
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My first thought was to add a field to CheckConstraintDescriptor. That approach
would require the addition of a new column in SYS.SYSCHECKS, which entails some
upgrade work.
I like the idea of rewriting the CHECK condition and making all unqualified
names qualified. Such a solution might be useful for generated columns, views
and triggers as well, since qualified names would make it easier to produce
correct dblook output for them (see for example DERBY-6370).
Not sure how easy it is to do the rewrite in a reliable way, though. It might
be possible to generalize the code in
DataDictionaryImpl.getTriggerActionString(), which replaces old/new transition
variables and transition tables with Java method calls or VTIs in trigger
actions. But I haven't looked into that.
Adding a new column to the system table and pushing the compilation schema
might be more robust, since the rewrite may easily miss some references if
we're not careful, or if we extend the allowed syntax later. But it's not as
elegant as rewriting.
> CHECK constraint uses wrong schema for unqualified routine invocations
> ----------------------------------------------------------------------
>
> Key: DERBY-6362
> URL: https://issues.apache.org/jira/browse/DERBY-6362
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.10.1.1
> Reporter: Knut Anders Hatlen
>
> DERBY-3944 fixed the problem with CHECK constraints invoking different
> routines depending on who performed the triggering INSERT or UPDATE statement.
> The discussion leading up to DERBY-3944 can be found here:
> http://mail-archives.apache.org/mod_mbox/db-derby-dev/200811.mbox/%[email protected]%3E
> Three alternatives are discussed in the thread:
> A) The schema that holds the CHECK constraint?
> B) The schema that holds the table?
> C) The current schema when the CREATE TABLE statement was issued?
> The conclusion in the thread was that option C was the correct one. However,
> what was implemented, was option B.
> I cannot find any information in DERBY-3944 about why option B ended up being
> chosen, so I assume that it was unintended.
> Here's an ij script that shows how the CHECK constraint tries to invoke the
> TO_HEX function in the schema of the target table (S2) instead of the schema
> that was the current schema at the time of CREATE TABLE:
> ij version 10.10
> ij> connect 'jdbc:derby:memory:db;create=true';
> ij> create schema s1;
> 0 rows inserted/updated/deleted
> ij> create schema s2;
> 0 rows inserted/updated/deleted
> ij> create function s1.to_hex(i int) returns char(4) language java parameter
> style java external name 'java.lang.Integer.toHexString' no sql;
> 0 rows inserted/updated/deleted
> ij> set schema s1;
> 0 rows inserted/updated/deleted
> ij> create table s2.t(x int, constraint cc check(to_hex(x) <> '80'));
> 0 rows inserted/updated/deleted
> ij> insert into s2.t values 1;
> ERROR 42Y03: 'TO_HEX' is not recognized as a function or procedure.
> (errorCode = 30000)
> ij> create function s2.to_hex(i int) returns char(4) language java parameter
> style java external name 'java.lang.Integer.toHexString' no sql;
> 0 rows inserted/updated/deleted
> ij> insert into s2.t values 1;
> 1 row inserted/updated/deleted
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