[
https://issues.apache.org/jira/browse/DERBY-3652?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Rick Hillegas updated DERBY-3652:
---------------------------------
Attachment: derby-3652-01-ab-mixTypesOnFirstPass.diff
Attaching second rev of patch, derby-3652-01-ab-mixTypesOnFirstPass.diff.
Again, no new tests yet. This version passes the regression tests. The first
version failed because the database metadata inspection of indexes ended up
relying on there being only one qualifying overload of
IndexDescriptorImpl.getKeyColumnPosition(). Unfortunately, there are two which
qualify under the ANSI method resolution rules, resulting in an ambiguity:
public int getKeyColumnPosition(int heapColumnPosition)
public java.lang.Integer getKeyColumnPosition(java.lang.Integer
heapColumnPosition)
That is, internal Derby code relies on non-ANSI method resolution rules. Two
approaches to this problem occurred to me:
1) Rework the internal Derby methods to remove the ambiguities.
2) Make the method resolver sensitive to whether it is resolving an internal
Derby method--user written procedures and functions are not allowed to bind to
internal Derby methods.
I thought that (1) was a bit more straightforward but also more likely to have
edge cases which we don't test for today. I opted for (2) as the less risky
alternative.
> Derby does not follow the SQL Standard when trying to map SQL routines to
> Java methods.
> ---------------------------------------------------------------------------------------
>
> Key: DERBY-3652
> URL: https://issues.apache.org/jira/browse/DERBY-3652
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.5.0.0
> Reporter: Rick Hillegas
> Attachments: derby-3652-01-aa-mixTypesOnFirstPass.diff,
> derby-3652-01-ab-mixTypesOnFirstPass.diff, SignatureMapping.html,
> SignatureMapping.html, SignatureProblems.java, signatureProblems.sql
>
>
> I have only tested this in the 10.5 trunk. However, I suspect that this
> affects all previous releases of Derby as well.
> In resolving method signatures for function/procedure invocations, the SQL
> standard makes the following definitions in part 13, section 4.5 (parameter
> mapping). These definitions, in turn, refer to tables B-1 and B-3 in JDBC 3.0
> Specification, Final Release, October 2001 ([JDBC]).
> * Simply mappable - This refers to the correspondence of SQL and Java
> types described in [JDBC] table B-1. This is the table which defines the
> mapping of SQL types to Java primitives.
> * Object mappable - This refers to the correspondence of SQL and Java
> types described in [JDBC] table B-3. This is the table which defines the
> mapping of SQL types to Java wrapper objects.
> * Output mappable - For OUT and INOUT parameters, this refers to a single
> element array whose cell is simply mappable or object mappable. E.g.
> Integer[] or float[].
> * Mappable - This means simply, object, or output mappable.
> * Result set mappable - This means a single element array whose cell is a
> type which implements either java.sql.ResultSet or
> sqlj.runtime.ResultSetIterator.
> Putting all of this together, section 4.5 continues:
> "A Java method with M parameters is mappable (to SQL) if and only if, for
> some N, 0 (zero) <= N <= M, the data types of the first N parameters are
> mappable, the last M - N parameters are result set mappable, and the result
> type is either simply mappable, object mappable, or void."
> Section 8.6 gives more detailed rules, but they are hard to follow. According
> to section 8.6, when resolving a routine invocation, Derby should expect to
> find one and only one static mappable method with the expected external name
> (Java class + method name).
> I believe that this is a fair description of the rules. This, at least, is
> what some other databases appear to do. See, for instance,
> http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.ase_15.0.java/html/java/java126.htm
> and
> http://www.service-architecture.com/database/articles/mapping_sql_and_java_data_types.html
> We do not have a regression test which verifies that Derby applies the SQL
> standard resolution rules. There may be several divergences from the
> standard. This JIRA is a place to track those discrepancies. Here is one that
> I have noticed:
> The following SQL signature
> ( a int ) returns int
> should be mappable to any of the following Java signatures
> public static int f( int a )
> public static int f( Integer a )
> public static Integer f( int a )
> public static Integer f( Integer a )
> However, I observe that Derby is only able to resolve the first and third
> signatures (the ones with primitive arguments). I will attach a test case
> showing this problem.
> I will also attach an html table summarizing the simply and object mappable
> rules.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
