Forms: Order By Attribute
A Pipe can be grouped and sorted by attributes of the input stream. These are set up in the Sort/Group tab of the Pipe form.
The following fields are configured on the Details tab:
| Field | Description |
|---|---|
| Maximum Number of Records Per Group | If a value is entered into this field, then when PhixFlow collates the input records into groups according to the specified Grouping Attribute Details (see below) once the maximum number of records have been added to the group any additional records for this group will be discarded. Records will be added to the group according to the specified sort order. This can be useful, for example, where you know that for a given set of grouping attributes you may get multiple records but you are only interested in the most recent record for that set. In this case you can configure the pipe to group by the grouping attributes, sort by an appropriate date attribute in descending order and set the Maximum Number of Records to 1. This will ensure that you only get the most recent record for the specified group when you read from this pipe. |
Form: Grouping Attribute Details
The following fields are configured for each grouping attribute:
| Field | Description |
|---|---|
| Attribute | Name of an attribute in the input stream. |
| Order | The position of this attribute in the list of sorting/grouping attributes. |
| Sort Direction | The direction of the sort based on this attribute: Ascending; or Descending. |
| Index Expression | If the pipe is configured as a Look-up with an index match type set, this field becomes available. Look-up pipes can be configured for fast "indexed" access to cached data. This data is collected from external tables, files or from other streams. Indexed access is controlled through configuring a pipe with an index and setting index expressions on "Group By" attributes here. |
| Group | If this attribute is part of the candidate key set, the Group flag must be ticked. Otherwise, the attributes will be used only to sort the data in the candidate set. |
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