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From "Mamta Satoor" <msat...@gmail.com>
Subject Re: more on system schema vs. user schema and character constants.
Date Thu, 31 May 2007 05:38:38 GMT
Dan, I am trying to understand the difference between connection's current
schema vs compilation schema of a statement. It will help me a lot if you
could talk about the 2 schemas in reference to an example.

thanks,
Mamta


On 5/30/07, Daniel John Debrunner <djd@apache.org> wrote:
>
> Mike Matrigali wrote:
> > I am sort of confused at this point, what we expect to be working
> > now and what should be.  What is the right way to write the
> > following query against a the system schema?  Is there anyway to
> > write the query without changing the default schema? :
>
> Not sure if it's related or not but I just noticed this code in CastNode
> and there is other similar fragments elsewhere in ValueNodes.
>
>     //set the collation type to be same as the current schema's
>     //collation type. Collation derivation is already initialized
>     //to correct value by default which is "IMPLICIT"
>     getTypeServices().setCollationType(
>   getLanguageConnectionContext().getDefaultSchema().getCollationType());
>
> I think this is incorrect. During compilation the correct value to get
> the current schema is using the getSchemaDescriptor(null) call for any
> node. The current schema for compilation will not match the connection's
> current schema in some situations, such as compiling an action statement
> for a trigger, a sps for metadata queries and possibly for views as well.
>
> If this code is frequent it might be worth creating a utility method in
> ValueNode as
>
> setSchemaCollation() {
>     getTypeServices().setCollationType(
>      getSchemaDescriptor(null).getCollationType());
> }
>
> Dan.
>
>

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