CREATE TABLE validation ( dummy char(1) );
INSERT INTO validation VALUES ( 'X' ); -- and make sure you do this only once
And then use as a validation query: SELECT * FROM validation;
Well. Yes. I am ashamed of reimplementing Oracle's "DUAL", but if you really want to know of a table that will always be there, provide it yourself.
And anyway, I mostly agree with Mike's statement about server-specific params in the config files: "Adding one more ... is not too much of a burden".
Only if you set the validation query from outside the config files, which is very unlikely, Mike's statement would not strictly apply IMHO.
Antonio Fiol
Derek Mahar wrote:
Thank you to all of you for your quick replies. It seems that the connection pool validation query is not specific to any database server implementation unless the query statement itself is server-specific (that is, it refers to a special server system database, table, or function). I like the idea of querying the server for the date, but I'm not sure that the date function is standard SQL and portable across all server implementations. Does anyone know otherwise?
Derek
-----Original Message-----
From: Peter Lin [mailto:[EMAIL PROTECTED] Sent: January 8, 2004 10:35 AM
To: Tomcat Users List
Subject: RE: Microsoft SQL Server validation query
in the past I just select the date from sql server. unless you want to test a specific table, but that has potential performance impact.
the safe simple query to see if sql server is alive is to just select the date.
peter lin
Allistair Crossley <[EMAIL PROTECTED]> wrote: I would not do that because that would return as many 1s as there are rows in the table. Something like count(*) may not be the most efficient but it returns just 1 row always. Also with using 1, you cannot guarantee a row will come back.
Allistair Crossley
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-----Original Message----- From: Michael Duffy [mailto:[EMAIL PROTECTED] Sent: 08 January 2004 15:25 To: Tomcat Users List Subject: RE: Microsoft SQL Server validation query
Or even "SELECT 1 FROM TABLE". No COUNT overhead, if any. - MOD
--- Allistair Crossley wrote:
i think you could use anything .. maybe
SELECT COUNT(*) FROM table
The dual table is an oracle dummy table and is quite handy, but I think the validation query can just be any old select statement that should return true a result always.
ADC
-----Original Message----- From: Derek Mahar [mailto:[EMAIL PROTECTED] Sent: 08 January 2004 15:15 To: Tomcat Users List Subject: Microsoft SQL Server validation query
Does anyone happen to know which validation query I should use for Microsoft SQL Server?
Derek
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