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copied!<p>For best performance, should get a look at our <a href="http://blog.synopse.info/post/2011/07/09/SynDBOracle:-Open-Source-native-Oracle-access" rel="nofollow noreferrer">Open Source direct access to Oracle</a>.</p> <p>If you are processing a lot of TQuery, without using the DB components, we have a dedicated pseudo-class to use direct OCI connection, as such:</p> <pre><code> Q := TQuery.Create(aSQLDBConnection); try Q.SQL.Clear; // optional Q.SQL.Add('select * from DOMAIN.TABLE'); Q.SQL.Add(' WHERE ID_DETAIL=:detail;'); Q.ParamByName('DETAIL').AsString := '123420020100000430015'; Q.Open; Q.First; // optional while not Q.Eof do begin assert(Q.FieldByName('id_detail').AsString='123420020100000430015'); Q.Next; end; Q.Close; // optional finally Q.Free; end; </code></pre> <p>And I've added some unique access via a late-binding Variant, to write direct code as such:</p> <pre><code>procedure Test(Props: TOleDBConnectionProperties; const aName: RawUTF8); var I: ISQLDBRows; Customer: Variant; begin I := Props.Execute('select * from Domain.Customers where Name=?',[aName],@Customer); while I.Step do writeln(Customer.Name,' ',Customer.FirstName,' ',Customer.Address); end; var Props: TOleDBConnectionProperties; begin Props := TSQLDBOracleConnectionProperties.Create( 'TnsName','UserName','Password',CODEPAGE_US); try Test(Props,'Smith'); finally Props.Free; end; end; </code></pre> <p>Note that all OleDB providers are buggy for handling BLOBs: Microsoft's version just do not handle them, and Oracle's version will <a href="https://stackoverflow.com/questions/6147274/is-oraoledb-provider-in-net-unreliable-on-clob-fields">randomly return null for 1/4 of rows</a>...</p> <p>On real database, I found out our direct OCI classes to be 2 to 5 times faster than the OleDB provider, without the need to install this provider. You can even use the <a href="http://www.oracle.com/technetwork/database/features/instant-client" rel="nofollow noreferrer">Oracle Instant Client</a> provided by Oracle which allows you to run your applications without installing the standard (huge) Oracle client or having an ORACLE_HOME. Just deliver the dll files in the same directory than your application, and it will work.</p>

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