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From Myrna van Lunteren <m.v.lunte...@gmail.com>
Subject Re: [jira] Closed: (DERBY-571) Virtual Table Mapping for no argument Diagnostic tables
Date Sat, 19 Nov 2005 07:25:56 GMT
Hi Dan,
 To get this documented in the manuals, do we need an extra JIRA, or are you
already taking care of this?
 Myrna

 On 11/18/05, Daniel John Debrunner (JIRA) <derby-dev@db.apache.org> wrote:
>
> [ http://issues.apache.org/jira/browse/DERBY-571?page=all ]
>
> Daniel John Debrunner closed DERBY-571:
> ---------------------------------------
>
>
> > Virtual Table Mapping for no argument Diagnostic tables
> > -------------------------------------------------------
> >
> > Key: DERBY-571
> > URL: http://issues.apache.org/jira/browse/DERBY-571
> > Project: Derby
> > Type: Improvement
> > Components: SQL
> > Reporter: Daniel John Debrunner
> > Assignee: Daniel John Debrunner
> > Priority: Minor
> > Fix For: 10.2.0.0 <http://10.2.0.0>
>
> >
> > Currently four no-argument diagnostic tables exist that provide
> information about the running state of Derby, or its error messages.
> > These tables are invoked using an awkward, non-standard syntax. As an
> example:
> > SELECT * FROM NEW org.apache.derby.diag.LockTable() as LOCK_TABLE
> > The improvement will provide an internal mapping from a regular table
> name in the SYSCS_DIAG schema
> > to the runtime virtual table code. Thus the above example would be
> replaced by:
> > SELECT * FROM SYSCS_DIAG.LOCK_TABLE
> > These diagnostic table expressions are regular table expressions (as is
> the NEW VTI construct) and
> > can be used wherever a normal table can.
> > Any DDL, INSERT/UPDATE/DELETE, compression procedure etc. that
> references a diagnostic table
> > will result in an exception.
> > The old style syntax will remain in place for 10.2, but become
> deprecated.
> > The tables to be implemented in this change are:
> > SYSCS_DIAG.LOCK_TABLE replaces org.apache.derby.diag.LockTable
> > SYSCS_DIAG.STATEMENT_CACHE replaces org.apache.derby.diag.StatementCache
> > SYSCS_DIAG.TRANSACTION_TABLE replaces
> org.apache.derby.diag.TransactionTable
> > SYSCS_DIAG.ERROR_MESSAGES replaces org.apache.derby.diag.ErrorMessages
> > Adding such a table will be table driven, thus easy for others to
> provide additional diagnostics.
> > Information about these diagnostic tables will not appear in the system
> catalogs or JDBC DatabaseMetaData.
> > The ResultSetMetaData for the any query involving a diagnostic table
> will be valid.
> > This is a first step in a progression towards supporing a fully
> application/user defined virtual table.
> > These steps are not part of this jira issue, but added for information
> purposes.
> > - second step - supporting diagnostic tables with parameters, e.g.
> > SELECT * FROM SYSCS_DIAG.SPACE_TABLE('sales', 'orders');
> > - third step - providing a create virtual table statement (most
> databases support
> > some form of virtual table, or wrappers). The DDL would be non-standard
> but the
> > data access would be standard. [need to check table functions in part 13
> of SQL standard]
> > E.g. syntax yet to be defined, but to give the general idea
> > CREATE VIRTUAL TABLE (TICKER VARCHAR(10), START TIMESTAMP, END
> TIMESTAMP)
> > LANGUAGE JAVA
> > PARAMETER STYLE JAVA
> > EXTERNAL NAME 'com.acme.stocks.historyFromYahooFinance';
>
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