PK generation
PK generation
- Subject: PK generation
- From: Ben Ketteridge <email@hidden>
- Date: Mon, 26 Apr 2004 17:07:18 +0100
I have a DB that does not provide Sequences in the same way as Oracle. However
it does provide me with the functionality by where the PK field of EO_PK_TABLE
is auto-incremented ON READ. Consequently I don't need to write to the table
EXCEPT when I'm generating a primary key for the first time on a given table.
I can't seem to persuade EOF to get primary keys from this EO_PK_TABLE either
by the standard method (not doing anything, except allowing EOF to believe
there is no sequence support), nor by overriding newPrimaryKeys in JDBCPlugin.
Anyone any suggestions? My code is attached.
Many TIA!
--
Kind Regards
Ben.
Dr Ben Ketteridge
email@hidden
Team Leader,
ProAct International,
PO Box 100, Denbigh, UK.
Tel: 01745 817161 ext. 322
/*
* Created on 26-Apr-2004
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Generation - Code and Comments
*/
package com.webobjects.jdbcadaptor;
import com.webobjects.foundation.*;
import com.webobjects.eoaccess.*;
import com.webobjects.eocontrol.EOFetchSpecification;
import com.webobjects.eocontrol.EOQualifier;
/**
* @author Ben Ketteridge
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Generation - Code and Comments
*/
public class CachePlugIn extends JDBCPlugIn {
/**
* @param arg0
*/
public CachePlugIn(JDBCAdaptor arg0) {
super(arg0);
}
public NSArray newPrimaryKeys(int count, EOEntity entity, JDBCChannel channel) {
if (count <= 0 || entity == null || entity.primaryKeyAttributeNames().count() > 1
|| channel == null || !channel.isOpen()) {
return new NSArray();
}
NSMutableArray ma = new NSMutableArray(count);
NSDictionary results = null;
Number pk = null;
EOSQLExpressionFactory expressionFactory = new EOSQLExpressionFactory(channel.adaptorContext().adaptor());
EOSQLExpression expression = (EOSQLExpression)expressionFactory.createExpression(entity);
expression.setStatement("select PK from "+primaryKeyTableName()+" where name = '"+entity.name()+"'");
EOAttribute pkCountAttribute = new EOAttribute();
pkCountAttribute.setName("PK");
pkCountAttribute.setColumnName("PK");
pkCountAttribute.setClassName("java.lang.Number");
pkCountAttribute.setValueType("i");
pkCountAttribute.setReadFormat("PK");
channel.setAttributesToFetch(new NSArray(pkCountAttribute));
for (int ii =0; ii < count; ii++) {
channel.evaluateExpression(expression);
results = channel.fetchRow();
if (results.count() > 0) {
pk = (Number)((NSKeyValueCoding)results.allValues().objectAtIndex(0)).valueForKey("PK");
}
else {
expression.setStatement("insert into "+primaryKeyTableName()+" (Name) values ('"+entity.name()+"')");
channel.evaluateExpression(expression);
pk = new Integer(1);
expression.setStatement("select PK from "+primaryKeyTableName()+" where name = '"+entity.name()+"'");
}
ma.addObject(new NSDictionary(pk, entity.primaryKeyAttributeNames().objectAtIndex(0)));
}
return ma;
}
}
_______________________________________________
webobjects-dev mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/webobjects-dev
Do not post admin requests to the list. They will be ignored.