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Ruby for Ingres via ODBC

Several months ago I decided to take a look at Ruby, in particular Rails, to see what all the fuss was about. Since Rails requires a database (of course) I thought I would see what could be done in getting it set up with Ingres. Since there is already someone working with a client of Ingres to produce a “native” Ingres driver for ruby I had a look at the ODBC offerings.

The default binding for ODBC appears to be available from http://www.ch-werner.de/rubyodbc/. Building the binding on Windows (this week I happen to be running windows) went ok. The subsequent tests did not go so well :(.

The following test fails:

$p = $c.proc("insert into test (id, str) values (?, ?)") {}
$p.call(3, "FOO")
$p[4, "BAR"]

An ODBC trace shows that integers as being passed to Ingres as SQL_VARCHAR. This sort of thing is allowed, if a little disagreable, with MySQL but Ingres does not like it.

If you apply the following patch to odbc.c the tests will complete:

diff -rup ruby-odbc-0.998/odbc.c ruby-odbc-0.998_patched/odbc.c
--- ruby-odbc-0.998/odbc.c      2006-05-21 09:38:30.000000000 +0200
+++ ruby-odbc-0.998_patched/odbc.c      2006-05-26 19:44:47.450091400 +0200
@@ -6151,6 +6151,7 @@ stmt_exec_int(int argc, VALUE *argv, VAL
        if (coldef == 0) {
            switch (ctype) {
            case SQL_C_LONG:
+               stype = SQL_INTEGER;
                coldef = 10;
                break;
            case SQL_C_DOUBLE:

Looking at the rest of the code more changes are needed since the ODBC binding sets the default type to SQL_VARCHAR without correcting for other types. If I get more time next week I will review the rest of the code in this function and post the complete diff.

Post a comment — Trackback URI RSS 2.0 feed for these comments This entry (permalink) was posted on Friday, May 26, 2006, at 7:08 pm by grant. Filed in ingres, odbc, ruby.
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