[h2] Check if an in-memory database exists

Discussion:

Nicholas DiMucci

2018-10-16 14:45:11 UTC

Is there a way to check if an in-memory database already exists besides
just attempting to querying it?

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Nicholas DiMucci

2018-10-16 14:53:04 UTC

Permalink

And why I say "querying it" I mean doing a SELECT and seeing if the table
exists.

Post by Nicholas DiMucci
Is there a way to check if an in-memory database already exists besides
just attempting to querying it?

Evgenij Ryazanov

2018-10-16 15:32:27 UTC

Permalink

Hello.

If you want to check presence of in-memory database you can add
;IFEXISTS=TRUE
to your database URL (something like
jdbc:h2:mem:database_name;IFEXISTS=TRUE).
With this argument an exception with error code 90013 will be thrown if
database is not exists.

If you want to check presence of a table in an opened database you can use
database metadata:
ResultSet rs = connection.getMetaData().getTables(null, "PUBLIC",
"TABLE_NAME", new String[] { "TABLE" });

if (rs.next) {
âŠ
}
or a query from INFORMATION_SCHEMA.TABLES.