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https://issues.apache.org/jira/browse/DERBY-3973?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rick Hillegas updated DERBY-3973:
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Attachment: DBMDWrapper.java
Attaching DBMDWrapper.java. To use this program:
1) Compile it under Java 6
2) Run the program in order to register the metadata methods as functions in
your Derby database. The program takes one argument, your database URL:
java DBMDWrapper "jdbc:derby:myDatabase"
3) Note that methods which return ResultSets are registered as table functions.
Methods which return scalar results are registered as scalar functions. Now you
can join metadata results via queries issued in an ij session like this:
select t.table_schem, t.table_name, c.column_name, c.type_name
from table( getTables( null, '%', '%' ) ) t,
table( getColumns( null, '%', '%', '%') ) c
where c.table_schem = t.table_schem
and c.table_name = t.table_name
and t.table_type = 'TABLE'
The program mostly follows the DatabaseMetaData api except for the following
issues:
- Boolean arguments and return values were changed from BOOLEAN to SMALLINT.
- Arguments of type int[] and String[] have been eliminated--they are
automatically wildcarded.
- The method getRowIdLifetime() has been commented out--Derby does not support
object types.
- The method getSchemas(String catalog, String schemaPattern) has been
commented out--it can be uncommented if the registration logic is made smarter
to handle the dropping of different overloads.
As extra credit, this program could be slightly modified so that you could use
Derby to run sophisticated joins against the metadata of other RDBMSes. To do
this, you would need to change the method getDefaultConnection() to return a
connection to the foreign RDBMS instead of to Derby.
> Create function wrappers for DatabaseMetaData so that you can join metadata
> results in queries.
> -----------------------------------------------------------------------------------------------
>
> Key: DERBY-3973
> URL: https://issues.apache.org/jira/browse/DERBY-3973
> Project: Derby
> Issue Type: Improvement
> Components: Demos/Scripts
> Affects Versions: 10.5.0.0
> Reporter: Rick Hillegas
> Assignee: Rick Hillegas
> Attachments: DBMDWrapper.java
>
>
> Create a program to wrap the DatabaseMetaData methods in Derby functions.
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