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Re: SQL Query Generation



WOnder has utility methods for getting a SQL COUNT(*) for a fetch spec and/or qualifier. In EO<something>Utilities.java ... You could use WOnder or use its code.

On Aug 10, 2007, at 6:12 PM, Michael Xenakis wrote:

All -

I'm trying to solve a lil' problem here.  The semi-short story is that prior to doing a fetch, I'm going to do a raw SQL fetch to determine how many rows would be returned - i.e., I'll do a "select count(*)" based on the search parameters.  If the count is greater than a predetermined fetch limit, then I respond w/ a message to further restrict the query.

To do this, I build my qualifiers as usual create a fetch spec based on the qualifiers and then pass them into a JDBCExpression.  The code looks like this:

        EOFetchSpecification fetchSpec = new EOFetchSpecification(entityName, searchQualifier, null);

        JDBCExpression sqlExpression = new JDBCExpression(entity);
        sqlExpression.prepareSelectExpressionWithAttributes(entity.attributes(), false, fetchSpec);

        String rawSQLQuery = "SELECT COUNT(*) FROM " + entity.externalName() + " WHERE " + sqlExpression.whereClauseString();
        if (!sqlExpression.joinClauseString().equals("")) {
            rawSQLQuery = rawSQLQuery + " AND " + sqlExpression.joinClauseString();
        }

Unfortunately, the where clause being generated by .whereClauseString() is parameterized, e.g.,
SELECT COUNT(*) FROM PLAYLIST t0, CONTENT_PROVIDER T1 WHERE (((t0.FIRST_PRODUCTION_RELEASE is not ? AND t0.LAST_PRODUCTION_RELEASE is ?) AND T1.CONTENT_PROVIDER_ID = ?) AND UPPER(t0.NAME) LIKE UPPER(?) ESCAPE '\')

What I can't seem to figure is how to get the string returned w/ the parameters replaced w/ the actual bound values.

So, first, am I heading down the right path or is there a better way?

If I am headed in the right direction, what am I missing?

Thanks,
mX.



Michael Xenakis
Architect
Übermind, Inc.
206.290.3362

IM: mgxenakis
AIM: Take2AndCa11Me


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References: 
 >SQL Query Generation (From: Michael Xenakis <email@hidden>)



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