Devo ottenere il valore massimo e minino dei valori giornalieri, mensili e annuali da una collection contentente i logger raccolti ogni 5 minuti.
la collection sorgente (Meteolog):
{ "_id" : ObjectId("50d5a8a01e05acfe08c086fb"), "className" : "it.marcoberri.mbmeteo.model.Meteolog" , "n" : 1643, "time" : ISODate("2012-12-09T00:33:00Z"), "interval" : 5, "indoorHumidity" : 65, "indo orTemperature" : 19.5, "outdoorHumidity" : 72, "outdoorTemperature" : -0.6, "absolutePressure" : 997 .2, "wind" : 0, "gust" : 0.3, "direction" : "SE", "relativePressure" : 1025, "dewpoint" : -5, "windc hill" : -0.6, "hourRainfall" : 0, "dayRainfall" : 6.9, "weekRainfall" : 12.3, "monthRainfall" : 12.3 , "totalRainfall" : 12.3, "windLevel" : 0, "gustLevel" : 1 }{ "_id" : ObjectId("50d5a8a01e05acfe08c086fc"), "className" : "it.marcoberri.mbmeteo.model.Meteolog" , "n" : 1644, "time" : ISODate("2012-12-09T00:38:00Z"), "interval" : 5, "indoorHumidity" : 65, "indo orTemperature" : 19.5, "outdoorHumidity" : 71, "outdoorTemperature" : -0.8, "absolutePressure" : 997 .3, "wind" : 0.3, "gust" : 0.7, "direction" : "S", "relativePressure" : 1025.1, "dewpoint" : -5.4, " windchill" : -0.8, "hourRainfall" : 0, "dayRainfall" : 6.9, "weekRainfall" : 12.3, "monthRainfall" : 12.3, "totalRainfall" : 12.3, "windLevel" : 1, "gustLevel" : 1 } la funzionalità di map sul singolo giorno (variabile time_short)
map = function(){
var fields =['outdoorTemperature','outdoorHumidity','absolutePressure','relativePressure','wind','gust','dewpoint','windchill','hourRainfall','dayRainfall','weekRainfall','monthRainfall','totalRainfall','windLevel','gustLevel'];
var objs = {};
for( var f=0; f<fields.length;f++) {
var k = fields[f];
objs[k] = { "min" : this[k], "max" : this[k]};
}
var time_short = this.time.getFullYear() + "-" + this.time.getMonth() + "-" + this.time.getDate();
emit(time_short,objs)
}La funzionalità di reduce:
reduce = function(key, values){
var fields =['outdoorTemperature','outdoorHumidity','absolutePressure','relativePressure','wind','gust','dewpoint','windchill','hourRainfall','dayRainfall','weekRainfall','monthRainfall','totalRainfall','windLevel','gustLevel'];
var res = values[0];
for ( var i=1; i<values.length; i++ ) {
for( var f=0; f<fields.length;f++) {
var k = fields[f];
var v = values[i][k];
if ( v.min < res[k].min )
res[k].min = v.min;
if ( v.max > res[k].max )
res[k].max = v.max;
}
}
return res;
}Usiamo le funzionalità:
db.Meteolog.mapReduce(map,reduce,{out:{merge:"reduceMaxMinDay"}});
db.reduceMaxMinDay.find();
result:
{ "_id" : "2012-11-23", "value" : { "outdoorTemperature" : { "min" : -2.3, "max" : 5.6 }, "outdoorHu midity" : { "min" : 79, "max" : 90 }, "absolutePressure" : { "min" : 996.8, "max" : 999 }, "relative Pressure" : { "min" : 1024.6, "max" : 1026.8 }, "wind" : { "min" : 0, "max" : 0.7 }, "gust" : { "min " : 0, "max" : 1 }, "dewpoint" : { "min" : -4.7, "max" : 2.4 }, "windchill" : { "min" : -2.3, "max" : 5.6 }, "hourRainfall" : { "min" : 0, "max" : 0 }, "dayRainfall" : { "min" : 0, "max" : 0 }, "weekR ainfall" : { "min" : 0, "max" : 0 }, "monthRainfall" : { "min" : 4.2, "max" : 4.2 }, "totalRainfall" : { "min" : 4.2, "max" : 4.2 }, "windLevel" : { "min" : 0, "max" : 1 }, "gustLevel" : { "min" : 0, "max" : 1 } } }{ "_id" : "2012-11-9", "value" : { "outdoorTemperature" : { "min" : -2.3, "max" : 13.4 }, "outdoorHu midity" : { "min" : 26, "max" : 75 }, "absolutePressure" : { "min" : 992.9, "max" : 999.4 }, "relati vePressure" : { "min" : 1020.7, "max" : 1027.2 }, "wind" : { "min" : 0, "max" : 1 }, "gust" : { "min " : 0, "max" : 1.7 }, "dewpoint" : { "min" : -7.3, "max" : 0.3 }, "windchill" : { "min" : -2.3, "max " : 13.4 }, "hourRainfall" : { "min" : 0, "max" : 8.1 }, "dayRainfall" : { "min" : 0, "max" : 12.3 } , "weekRainfall" : { "min" : 0, "max" : 20.4 }, "monthRainfall" : { "min" : 0, "max" : 20.4 }, "tota lRainfall" : { "min" : 0, "max" : 20.4 }, "windLevel" : { "min" : 0, "max" : 1 }, "gustLevel" : { "m in" : 0, "max" : 2 } } } etc.per modificare il periodo di calcolo basta modficare la variabile che permette il raggruppamento delle info:
es: mesile --> var time_short = this.time.getFullYear() + "-" + this.time.getMonth();
es: annulale --> var time_short = this.time.getFullYear();
