Problem using Lookups

ciscochi

• September 09, 2009 00:00

• Answered

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Hi,
I've searched the forum but didn't see anything with this very basic problem, so I suspect it is something I am missing from the user guide.

I am having trouble with DB Lookups. I've defined a DB lookup a few different ways:
- query like: select * from dim
- query like: select name, id from dim
- no metadata
- metadata with name, id

I'm unable to reference this lookup. In my reformat, I do:
lookup(LookupTable0, $0.name).id

When I run the graph, I get the following error:
Interpreter runtime exception on line 20 column 51 : java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0). with field '_field0' when mapping...

In other tools, I have to specify a key, but I didn't see where I specified this.

What am I doing wrong?

*** One gripe I have about lookups is that I don't see a way to change the ID, which is what is used in all the references to it. I don't understand why we don't just use the logical names to reference the lookups, like Ab Initio.

• 

  ciscochi

  • September 10, 2009 06:43

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  I figured this one out. The picture in the user guide was tiny, but I noticed after posting.
  
  I'm not sure if this implementation of DB lookup is very performant. I got 3x better throughput by implementing a hash join with the lookup as an input table in the slave port.

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