a tool to reverse-engineer a schema
Has anyone extended DBD::Null to make a tool that after you run a mess of prepare statements against the handle, it will give you some DDL to create a schema that they will all make sense on? -- I like to think that when I ramble on, I'm speaking for others who share my opinions or point of view but who aren't as expressive.
Re: a tool to reverse-engineer a schema
I mean of course DBD::Mock, sorry http://search.cpan.org/~drolsky/DBD-Mock-1.39/lib/DBD/Mock.pm On Tue, Apr 27, 2010 at 9:24 AM, David Nicol davidni...@gmail.com wrote: Has anyone extended DBD::Null to make a tool that after you run a mess of prepare statements against the handle, it will give you some DDL to create a schema that they will all make sense on?
RE: a tool to reverse-engineer a schema
David- My understanding of database design is that a database is used to organise the data.. so the upfront work of define tables..columns and their relationships..DDL usually comes first if a bunch of statements are thrown at the Database the database could conceivably cache those statements and then create and or modify the schema? you might want to consider an ORM (Object Relation Mapper) such as hibernate and specify lazy=true (load data only when needed) http://www.coderanch.com/t/218722/Object-Relational-Mapping/java/fetching-lazy more specifically you will want to control of when to create your schema entities are created via the hbm2ddl.auto option which will turn on automatic generation of database schemas directly into the database. http://docs.jboss.org/hibernate/stable/core/reference/en/html/tutorial.html#tutorial-firstapp-workingpersistence hth Martin Gainty __ Note de déni et de confidentialité Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. From: davidni...@gmail.com Date: Tue, 27 Apr 2010 09:26:40 -0500 Subject: Re: a tool to reverse-engineer a schema To: dbi-users@perl.org I mean of course DBD::Mock, sorry http://search.cpan.org/~drolsky/DBD-Mock-1.39/lib/DBD/Mock.pm On Tue, Apr 27, 2010 at 9:24 AM, David Nicol davidni...@gmail.com wrote: Has anyone extended DBD::Null to make a tool that after you run a mess of prepare statements against the handle, it will give you some DDL to create a schema that they will all make sense on? _ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2
Re: dbd::oracle behavior
Ouch Sorry late reply on this one If you are using an earlier version of DBD::Oracle and Apache::DBI you might be seeing the 'PING' effect. To keep connections alive in Apache::DBI it uses the $h-ping which in older DBD does a select on a table. 260 and 360 are not very many. I have seen rates well into the 1s for some other users version 1.22+ fixed this by doing either an OCIPing if you are using 10+ client or another OCI call that does a round trip to the server. Hope this helps cheers John Scoles Matthew Maglinte wrote: I'm a dba supporting a warehouse database (production environment) accessed via a custom application built on open source components, one of which is dbd::oracle. Performance monitoring shows two queries continually consuming considerable resources (cpu waits) - the query text resembling for the most part 'column_info' and 'table_info'. Over any given day, the column_info select is executed +260 times an hour, 'table_info' executed +360 times an hour. Is this level of frequency intended? And are these calls appropriate (expected) for a static data dictionary environment? Any response that would help my understanding would be appreciated. Thanks. Matt Maglinte DBA - PeMS/LCS Department of Transportation W:(916)445-0090 matthew_magli...@dot.ca.gov
