Writing to KDB using qJava
I'm not very good with KDB (in case the question sounds silly). I am trying to use kdb (disk not memory) to load all my data from the database. I already asked a question about upserts and I figured out how to take off from console and save to disk
q)dsPricing:([id:`int$(); date:`date$()] open:`float$();close:`float$();high:`float$();low:`float$();volume:`int$())
q)dsPricing:([id:`int$(); date:`date$()] open:`float$();close:`float$();high:`float$();low:`float$();volume:`int$())
q)`dsPricing insert(123;2003.03.23;1.0;3.0;4.0;2.0;1000)
q)`dsPricing insert(123;2003.03.24;1.0;3.0;4.0;2.0;2000)
q)save `:dsPricing
q)`:dsPricing upsert(123;2003.03.25;1.0;3.0;4.0;2.0;1500)
Now I am trying to do it in Java and have the following code
public class LoadDS {
SqlSession session;
private DataStreamMapper mapper ;
public static void main(String args[]){
final QConnection q = new QBasicConnection(args.length >= 1 ? args[0] : "localhost", args.length >= 2 ? Integer.parseInt(args[1]) : 5001, "user",
"pwd");
LoadDS l=new LoadDS();
l.session = MyBatisConnectionFactory.getSqlSessionFactory("SMALLS").openSession();
l.mapper = l.session.getMapper(DataStreamMapper.class);
List<DataStream> prices = l.mapper.selectHistoricalPrices(1);
try {
q.open();
q.sync("upsert", "'dsPricing", l.getData(prices));
} catch (QException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// dsPricing:([id:`int$(); date:`date$()] open:`float$();close:`float$();high:`float$();low:`float$();volume:`int$())
private Object[] getData(List<DataStream> prices) {
final Object[] data = new Object[] {new int[prices.size()], new QDate[prices.size()],
new float[prices.size()], new float[prices.size()],
new float[prices.size()],new float[prices.size()],
new int[prices.size()]
};
for ( int i = 0; i < prices.size(); i++ ) {
((int[]) data[0])[i] = prices.get(i).getInfoCode();
((QDate[]) data[1])[i] = new QDate(prices.get(i).getMarketDate());
((float[]) data[2])[i] = (float)prices.get(i).getOpen_();
((float[]) data[3])[i] = (float)prices.get(i).getClose_();
((float[]) data[4])[i] = (float)prices.get(i).getHigh();
((float[]) data[5])[i] = (float)prices.get(i).getLow();
((int[]) data[6])[i] = (int)prices.get(i).getVolume();
}
return data;
}
}
Can anyone tell me what I am doing wrong? No data is saved and I tried several options. I'd rather just load the data from SQL and save it to disk for bootstrapping.
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2 answers
Thanks to Charles Skelton of Kx Systems
public static void main(String[]args){
try{
c c=new c("",5001);
c.k("addData",new Object[]{new int[]{1,1},
new Date[]{Date.valueOf("1994-2-17"),Date.valueOf("1994-2-16")},
new double[]{73.,76.},
new double[]{73.,76.},
new double[]{76.,77.899994},
new double[]{73.,75.},
new int[]{2223000,3167000}});
c.close();
}
catch(Exception e){
e.printStackTrace();
}
}
then confirm data availability
q)addData:{`:dsPricing/ upsert flip `id`date`open`close`high`low`volume!x;}
q)select from `:dsPricing
id date | open close high low volume
-------------| -------------------------------
1 1994.02.17| 73 73 76 73 2223000
1 1994.02.16| 76 76 77.89999 75 3167000
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