In general field tags allows for adding metadata to the fields in your data model. Automatic field tagging in Qlik Sense has changed in February 2019 as a symptom of how unrecognized data format is treated by Qlik Sense.Environment:
- Qlik Sense Enterprise, February 2019 and later
Most unrecognized formatting from a data source are treated as a text representation in February 2019 and later. Previously, these formats where interpreted numerically, often with incorrect results. For example in Qlik Sense November 2018 version, data fields (defined as text fields in the data source) containing yearmonth data (yyyymm) are read as a number/integer. In February 2019 and later versions, those data fields are read as ascii/text. See related documentation under Qlik Sense: Date picker field shows invalid dimension error
There has been a feature request registered in order to allow a method for which this behavior may be reverted.Feature Request ID(s):
- 3147 - Ability to revert to legacy value interpreting behavior for unrecognized formatting
There is an automatic field tagging based on the content of the data field, but if you want to control the field types you can use num() and text() function in your load statement to cast each field to the type you want to.
When needing to influence the actual metadata tagging for a field the tag() and untag() functions may be used.
For more information see: Field Tags