Thread: Connecting a postgresql client to an oracle7 db
Hello, Is it possible to connect the postgresql program psql to an oracle7 database ? When I tried I got: bash$ psql -h nan -p 1526 satbase psql: PQconnectDB() -- couldn't read postmaster response: errno=2 No such file or directory and on the server side the listener.log file reads: 05-FEB-02 16:36:51 * 12569 TNS-12569: TNS:packet checksum failure On the network, tcpdump saw this: 17:08:35.251072 eth1 > desire.45256 > nantes.1526: S 774363043:774363043(0) win 5840 <mss 17:08:35.261072 eth1 < nantes.1526 > desire.45256: S 499968000:499968000(0) ack 774363044 17:08:35.261072 eth1 > desire.45256 > nantes.1526: . 1:1(0) ack 1 win 5840 (DF) 17:08:35.261072 eth1 > desire.45256 > nantes.1526: P 1:297(296) ack 1 win 5840 (DF) 17:08:35.271072 eth1 < nantes.1526 > desire.45256: F 1:1(0) ack 297 win 32768 (DF) 17:08:35.271072 eth1 > desire.45256 > nantes.1526: F 297:297(0) ack 2 win 5840 (DF) 17:08:35.271072 eth1 < nantes.1526 > desire.45256: . 2:2(0) ack 298 win 32768 (DF) Thank you for any help. Dominique Duflos
Dominique, > Is it possible to connect the postgresql program psql to an oracle7 > database ? Well, no. Why not use Oracle's own tools? -Josh Berkus
Josh Berkus wrote: > > Is it possible to connect the postgresql program psql to an oracle7 > > database ? > > Well, no. Why not use Oracle's own tools? > Ah... Reading the FAQs of PostgresQL and learning that SQL was very standardized, I had thought I could write an application that could connect to any SQL-implementing database on our intranet. Thanks for the quick and definite reply. DD
Domenique, > Ah... Reading the FAQs of PostgresQL and learning that SQL was very > standardized, I had thought I could write an application that could > connect to any SQL-implementing database on our intranet. You can. You just need to use each database's *external* interfaces, through ODBC, JDBC, or similar data transmission tools. Psql, like Microsoft's Query Analyzer, connects with the database at a more "intimate" level where commands are sent directly in the database's internal API ... which is *never* standard. But with Java, Perl, PHP, C++ or COM you should ba able to write an application that connects to all SQL databases. HOWEVER, Postgres upholds only about 80% of the standard, and most other databases have less. Oracle, for example, uses a completely non-standard notation for Outer Joins that is not compatible with any other database, nor will it recognize SQL standard syntax for Outer Joins. This will remain a problem for you even when you use JDBC or similar to connect. If you are going to go ahead with this project, I suggest that you: 1. Read the various "porting" documents at http://techdocs.postgresql.org/ 2. Buy a copy of "SQL In a Nutshell" from O'Reilly, which has feature-for-feature and command-by-command comparison of Postgres, MySQL, Oracle, and SQL Server (though it is 1.5 years out of date). 3. REsearch on the Net. It may be that some kind of "database compatibility layer" that allows you to use a single standard syntax to address all of your databases exists somewhere, either as Open Source or for a fee. -Josh Berkus ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete information technology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco
"Josh Berkus" <josh@agliodbs.com> writes:
> ... Oracle, for example, uses a completely
> non-standard notation for Outer Joins that is not compatible with any
> other database, nor will it recognize SQL standard syntax for Outer
> Joins.
I was under the impression that Oracle *does* accept the standard
outer-join syntax. But there's a lot of people who are used to their
legacy syntax, and a lot of application code that still uses it.
regards, tom lane
Josh Berkus wrote: > > I had thought I could write an application that could > > connect to any SQL-implementing database on our intranet. > > You can. You just need to use each database's *external* interfaces, > through ODBC, JDBC, or similar data transmission tools. > I will learn about ODBC and see if I can write a tool over it in Tcl. We only need very simple operations: open the DB, get a table content, then close. Thanks to all. Dominique Duflos.