Field tags provide the possibility of adding metadata to the fields in your data model. There are two different types of field tags:
-
System field tags
System field tags are generated automatically when the script is executed and data is loaded. Some of the tags can be manipulated in the script. System tags are always preceded by a $ sign.
-
Custom field tags
You can add custom tags to fields in the load script, using the Tag statement. Custom tags may not use the same name as any system tag.
System field tags
The following system field tags are generated at the end of script execution.
| Tag | Description | Can be manipulated in the script |
|---|---|---|
| $system |
System field that is generated by QlikView during script execution. |
No |
| $key | Key field providing a link between two or more tables. | No |
| $keypart | The field is part of one or more synthetic keys. | No |
| $syn |
Synthetic key |
No |
|
$hidden |
Hidden field, that is, it is not displayed in any field selection list when creating charts, dimensions or measures. You can still use hidden fields in expressions, but you need to type the field name. You can use the HidePrefix and HideSuffix system variables to set which fields to hide. |
Yes |
| $numeric | All (non-NULL) values in the field are numeric | Yes |
| $integer | All (non-NULL) values in the field are integers. | Yes |
| $text | No values in the field are numeric. | Yes |
| $ascii | Field values contain only standard ASCII characters. | Yes |
| $date | All (non-NULL) values in the field can be interpreted as dates (integers). | Yes |
| $timestamp | All (non-NULL) values in the field can be interpreted as time stamps. | Yes |
The following tags are set in the Document Properties: Tables dialog and can be enabled and disabled by the user:
- $dimension - denotes a field recommended for use in chart dimensions, list boxes, etc.
- $measure - denotes a field recommended for use in expressions.
