Обсуждение: Creating a database with JDBC

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Creating a database with JDBC

От
Richard Heller
Дата:
Hi,

Is there any way to connect to the postgresql driver without having a
database already in existence?  I want to have a Java program that can
check if a database already exists and create the database if it doesn't
exist.

The examples I've seen all seem to assume that a database has already been
created.

Thanks,
Rich



Re: [INTERFACES] Creating a database with JDBC

От
Herouth Maoz
Дата:
At 19:22 +0200 on 27/9/98, Richard Heller wrote:


> Is there any way to connect to the postgresql driver without having a
> database already in existence?  I want to have a Java program that can
> check if a database already exists and create the database if it doesn't
> exist.
>
> The examples I've seen all seem to assume that a database has already been
> created.

Not only for Java, but generally for Postgres: There is always a
"template1" database. That database gets created when you install Postgres.
If you want to issue database-manipulation commands in SQL, all you need to
do is to connect to "template1" as your database, and issue SQL commands
such as CREATE DATABASE.

If you want to detect whether a database exists, I think the information is
in one of the system catalogs, but I don't remember exactly which. Another
solution, of course, is to attempt to connect to it, and if the attempt
fails (should probably check what error message was returned), connect to
template1 and issue a CREATE DATABASE statement.

By the way, make sure your postgres server runs with the -i option, or you
won't be able to connect to it with Java.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma



Re: [INTERFACES] Creating a database with JDBC

От
"Cary B. O'Brien"
Дата:
> Hi,
>
> Is there any way to connect to the postgresql driver without having a
> database already in existence?  I want to have a Java program that can
> check if a database already exists and create the database if it doesn't
> exist
>
You should be able to connect to template1 and select * from pg_database
to see what databases exist.

-- cary