Streams are a key modelling components in PhixFlow.Streams are configured through the Stream properties. This page is for data modellers. It provides an introduction to streams and pipes.
In an analysis model a data set is represented by a stream. A stream is a bit like an Excel spreadsheet, in that it contains a set of data with:
- columns - these are the stream attributes
- rows - these are the data records.
Streams are connected to other modelling objects via pipes; see by pipes. A pipe sends data from the input object to the output object. Objects are usually streams, but there are also objects to load and export data, such as a datasource or file exporter. Usually a pipe with the default settings passes all attributes and records onto the next object. However, you can use the pipe properties to control which attributes and records from the input object you want to pass through.
When you run an analysis model, the data is processed. This means the data set in a stream can change with each anaysis run. This means, unkike Excell, each stream can have multiple data sets over time. These are called stream sets.
A pipe is a connector that links two elements in a PhixFlow model and sends data from the input to the output. Pipes allows you to control which attributes and which records from the input are delivered by to the output, although in most cases - with minimal configuration - you will get all columns and the records from the current run.
See also:
Types of Stream
There are several types of stream.
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Publishing Streams
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When you make changes to a stream's properties or its attributes, PhixFlow publishes the changes to the stream data tables in the PhixFlow database. This happens automatically in the background. Publishing many streams or streams with many attributes can take some time, and may slow performance.
If the stream properties are set incorrectly, PhixFlow will not be able to publish the stream data to the database. If this happens, the
will report the publishing error. PhixFlow will also display an error message if you try to interact with the stream, for example to view its data or to run analysis. You must correct the stream properties, so that PhixFlow can retry publishing the stream. Insert excerpt _console _console nopanel true
During the publishing process, PhixFlow may create temporary tables in its database. These are kept for a period, then automatically removed when a system task runs. For information about:
- the system task, see Using Tasks and Task Plans
- configuring the period that temporary tables are kept; see System Configuration → Delete Temp Tables after Days.