Post by b***@gmail.comPost by k***@gmail.comI am using EasySoft's odbc driver on a Linux box.
I can successfully connect to the datasource which access legacy C-ISAM
files. But I want to regularly access these files from a real database
under IDS. How to I do an odbc connect from dbaccess OR ESQL-C?
I have the same question. Have you found a solution?
DB-Access uses ESQL/C, not ODBC, to connect to the database.
ESQL/C does not use ODBC and ODBC does not use ESQL/C, but both use an
underlying library, the SQLI library, to connect to Informix databases.
If you want to connect to C-ISAM files via ODBC and use cross-table SQL
queries, etc, you need an SQL DBMS. C-ISAM is not an SQL DBMS; it is a
relatively simple storage engine.
Formally, you have a few options:
1. Migrate the C-ISAM data to a regular Informix database (IDS, in other
words). I have tools to export C-ISAM files if you know the schema of
those files.
2. Migrate the C-ISAM data to an Informix Standard Engine (SE) database.
There are tricks and caveats involved here, but in principle you can then
use ODBC to access the C-ISAM data. One issue is the C-ISAM only supports
a fairly archaic version of SQL. It doesn't support 'sub-queries in the
FROM clause' or standard JOIN notations, for example.
3. Use the C-ISAM datablade. This has two modes of operation. One permits
IDS to access C-ISAM data stored in C-ISAM files outside the IDS server.
The other permits C-ISAM programs to access data inside IDS as if it were
still in C-ISAM files (relinking required).
Of these, (1) is the best in the long term. Either of the other two will
work if the limitations are acceptable. A lot depends on whether you have
C-ISAM program still needing to access the C-ISAM files.
--
Jonathan Leffler <***@gmail.com> #include <disclaimer.h>
Guardian of DBD::Informix - v2011.0612 - http://dbi.perl.org
"Blessed are we who can laugh at ourselves, for we shall never cease to be
amused."