On Mar 2, 2009, at 4:26 PM, Kieran Kelleher wrote:
Hi Chuck,
I was half-expecting this outcome, especially after examining how
the different SQLHelpers implement limitSqlExpression method. I am
tempted to implement an ERXSpec subclass though to auto limit for
databases with supported ERXSqlHelpers ...... it just seems like the
right default behaviour to have....
I don't have any arguments against it. I am not sure if fetch spec is
the place for this, probably lower in EOAccess.
Chuck
Thanks, Kieran
On Mar 2, 2009, at 6:43 PM, Chuck Hill wrote:
On Mar 2, 2009, at 1:42 PM, Kieran Kelleher wrote:
I always thought that EOFetchSpecification.setFetchLimit( int n)
would generate SQL with LIMIT n tacked onto the end of the SQL
statement, but it appears not to.
This is the default behavior as not all databases implement this.
Specific plugins add this, IIRC.
Chuck
Instead it fetches the all qualifying records and does the LIMIT
in memory?! Has this always been the case .... or is it just the
MySQL driver?
For example:
<snip>
// Fetch the most recent shipped message
ERXSortOrderings s = CTMessage.XKEY_OID.descs();
ERXFetchSpecification<CTMessage> fs = new
ERXFetchSpecification<CTMessage>(CTMessage.ENTITY_NAME,null,s);
fs.setFetchLimit(1);
System
.out.println("MailingAddressUtilitiesTests.suppressionTest():
fs.SQL = " + ERXEOAccessUtilities.sqlForFetchSpecification(ec, fs));
NSArray<CTMessage> objects = fs.fetchObjects(ec);
</snip>
..... generates the following SQL without "LIMIT 1" !!!
SELECT t0.oid, t0.oidcampaign, t0.oiddatarecord, t0.oidjob,
t0.oidlocation, t0.oidmediatemplate, t0.recaddtime, t0.recadduser,
t0.recmodtime, t0.recmoduser, RTRIM(t0.workflowstate) FROM message
t0 ORDER BY t0.oid DESC;
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Practical WebObjects - for developers who want to increase their
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--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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