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Calculated attribute (data source)

Calculated attribute via a data source – with context variables and dynamic background colour for the web client.

HOW-TO APPLICATION DEVELOPER STAND: JUL 2026 GILT FUER NUCLOS 4.2026.X

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What is a calculated attribute (data source)?

A calculated attribute is a single return value of a database query that is linked to a field in the business object and shown at runtime – without any user action.

Menu: Configuration → Data sources → Calculated attribute

Advantage

Compared to functions in database objects, data-source-based attributes offer extra context variables such as $username and $mandator (the latter must be bracketed: ('$mandator')).

Structure

The data source needs a parameter for the INTID of the record where the attribute is shown. The return value must match the value to display; the same data type is chosen when linking it in the business object.

Caution

Do not use t as a table alias in the data source – it is already used by Nuclos and leads to wrong results. Reference fields cannot be calculated.

Businessobjekt

Data source of a calculated attribute.

Dynamic background colour (from Nuclos 4.2024.5)

Since Groovy scripts are not evaluated in the web client, a data source of type calculated attribute can return a component's background colour as a hex-encoded string (e.g. #00ff00). Available parameters include: intid, strfield, struidfield, fieldvalue (SQL snippet, whitelist attributeColorSQLWhitelist), username, mandator.

select 
  pm.strvalue 
from 
  t_md_nucletparameter 
  inner join t_md_mandator_param_value pm on t_md_nucletparameter.struid 
where 
  pm.struid_t_md_nuclet_param where strparameter = 'Nucletparameter x' 
  and pm.struid_t_md_mandator = ('$mandator')

Hierarchy

Priority rich client: Groovy > data source > nuclosrowcolor > static layout colour. Web client: data source > nuclosrowcolor > static layout colour.