How to check connection to DB without having the db its tables names

The point here is that I don't have the data base table开发者_开发技巧 names so please don't suggest to choose one table on to do on it 'SELECT COUNT(*)'

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This depends on the database, but usually there are some tables that always exist or a table isn't even required.

For Oracle:

SELECT 1 FROM dual

For SqlServer:

SELECT 1

Not very elegant, but generally does the job if you know the database brand.

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You haven't said what database type it is, but you could use something like DbConnection.GetSchema which is bound to need a working connection. I don't know how heavy a hit that would be though... if you knew more about the database type there may be a simpler "heartbeat" query you could perform.

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You could run a command that doesn't query against a table, such as:

select @@VERSION