aggregation

First there is a similar unanswered question Joining routes into single aggregator We have some consumer routes (ftp, file, smb) reading files from remote systems. Simplified for test with direct route, but similar behavior with batch consumers: from("direct:"+routeId).id(routeId) .setProperty(AGGREGATION_PROPERTY, constant(routeId)) .log(String.format("Sending (${body}) to %s", "direct:start1")) .to("direct:aggregate"); After transformation all results from one poll are aggregated by batch in a separate route: from("direct:aggregate") .aggregate(property(AGGREGATION_PROPERTY), new

horrible title, but let me explain: i've got this django model containing a timestamp (date) and the attribute to log - f.e. the number of users consuming some ressource - (value). class Viewers(models.Model): date = models.DateTimeField() value = models.IntegerField() for each 10seconds the table contains the number of users. something like this: | date | value | |------|-------| | t1 | 15 | | t2 | 18 | | t3 | 27 | | t4 | 25 | | .. | .. | | t30 | 38 | | t31 | 36 | | .. | .. | now i want to generate different statistics from this data, each with another resolution. f.e. for a chart of the last

In my Django application, using Postgresql, I have a model with an ArrayField of CharFields. I would like to know if there's a DB way to aggregate and get a list of all the strings in the table. For example: ['dog', 'cat'] ['dog'] ['cat'] would yield ['dog', 'cat'] I know how to do that in Python but would like to find out a way to aggregate this on the DB level. Using Django 1.8.4 In PostgreSQL you can do the following: SELECT DISTINCT UNNEST(array_column) FROM the_table; So if your model looks something like class TheModel(models.Model): # ... array_field = ArrayField(models.CharField(max

As the Aggregation and Composition is related Association or we can say it gives the understanding of relationship between object or anything else. I posted this question because i asked one question in Interview that what is the Composition and Aggregation. So as per my understanding i given my idea which is as follow. http://www.coderanch.com/t/522414/java/java/Association-Aggregation-Composition Aggregation, Association and Composition Association vs. Aggregation vs. Composition in Java and also visited much more. and my basic explanation was related that Aggregation indicates loose

I always thought that the UML aggregate is defined as a black (filled) diamond at the beginning of a path and no arrow head that the end: |--------| |--------| | :MyA |<>------| :MyB | |--------| |--------| Today I came across a notation like <>-----> (with an explicit arrow head on the right end). So I looked it up in the UML 2.4 specification and actually found references for both versions. My favourite reference: "UML and Patterns" by Craig Larman only mentions the first version without the arrow. In the UML specification I found a notice about navigable ends , but I am not sure if this is

I can create an array of arrays: select array[array[1, 2], array[3, 4]]; array --------------- {{1,2},{3,4}} But I can't aggregated arrays: select array_agg(array[c1, c2]) from ( values (1, 2), (3, 4) ) s(c1, c2); ERROR: could not find array type for data type integer[] What am I missing? I use: CREATE AGGREGATE array_agg_mult(anyarray) ( SFUNC = array_cat, STYPE = anyarray, INITCOND = '{}' ); and queries like: SELECT array_agg_mult( ARRAY[[x,x]] ) FROM generate_series(1,10) x; Note that you must aggregate 2-dimensional arrays, so you'll often want to wrap an input array in a single-element

I am looking for patterns for manipulating data.table objects whose structure resembles that of dataframes created with melt from the reshape2 package. I am dealing with data tables with millions of rows. Performance is critical. The generalized form of the question is whether there is a way to perform grouping based on a subset of values in a column and have the result of the grouping operation create one or more new columns. A specific form of the question could be how to use data.table to accomplish the equivalent of what dcast does in the following: input <- data.table( id=c(1, 1, 1, 2, 2,