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Re: LDBC driver

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  To: comp.lang.java.databases
Lew wrote:
> blueparty wrote:
>> http://ldbc.sourceforge.net/
>>
>> Any experiences, opinions, anything to share ?
> 
> I don't see the advantage over JDBC.
> 
> They say that with JDBC,
>> # The SQL is different for each databases
>> # Every JDBC driver behaves differently
>> # Changes are required for each database
>> # No time to study all vendor documentation
>> # No time to test with all databases
> 
> However, with JDBC, and especially with JPA, much of the difference 
> between vendors is already abstracted.  Also, most products are designed 
> to work with a single database engine; not as many are meant to plug 
> into virtually any RDBMS, and those tend to be written with a generic 
> SQL dialect in the first place.
> 
> Where RDBMSes differ the most is in DDL, which is generally outside the 
> scope of the Java program and not such an issue there.
> 
> With modern data layers like Hibernate and other JPA solutions, the 
> differences the program does care about are moved off into deployment 
> descriptors.  These guys achieve their "independence" by using the same 
> restricted dialect of SQL as you'd use without LDBC if you were to try 
> to be portable.
> 
> I can see a niche for it in those few products that are meant to plug 
> into any database, maybe.  But for my own work, no thank you.  I'll 
> stick with the standard approaches.  Last thing I need in my alphabet 
> soup is yet one more layer to go wrong on top of the gazillion layers of 
> abstraction already in place.
> 

I totally agree. My company does supply a system that runs on most major 
databases (we use PostgreSQL ourselves on our ASP platform but we have 
customers with private installations using Oracle, SQLServer and MySQL) 
and as Lew said the relevant differences are in the DDL area mostly.

One extra problem we had to solve was storing UUID values. Some 
databases have direct support for this data type but the JDBC drivers 
expose them differently. Some don't support UUIDs directly and in those 
cases we revert to a binary or plain text representation.

We have solved the differences at the DDL level by generating different 
database create/drop/etc. scripts using vendor specific XSLT 
transformations on a generic XML database descriptor.

The PreparedStatement-parameter and ResultSet-getXXX differences we have 
solved by creating a set of JDBC wrappers for the Connection, 
PreparedStatement and ResultSet classes that add extra methods like 
setUUID(...) and getUUID.
Since we already used such wrappers in combination with our connection 
pool to handle automatic closing of resultsets and statements when 
connections are returned to the pool (and a facility that allows 
specification of -1 as the parameter-index on a PreparedStatement and 
have it do the counting itself) this was a small modification even as an 
afterthought.

Silvio

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Re: LDBC driver "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
  Re: LDBC driver "Silvio Bierman" <silvio.bierman@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
  Re: LDBC driver "Thomas Kellerer" <thomas.kellerer@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
    Re: LDBC driver "Silvio Bierman" <silvio.bierman@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
      Re: LDBC driver "Thomas Kellerer" <thomas.kellerer@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
        Re: LDBC driver "Silvio Bierman" <silvio.bierman@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
      Re: LDBC driver "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000
        Re: LDBC driver "Silvio Bierman" <silvio.bierman@THRWHITE.remove-dii-this> - 2011-04-27 15:22 +0000

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