Which parameter is used to create a set of time-based or duration-based dimensions all at once?

The parameter used to create a set of time-based or duration-based dimensions all at once is the dimension_group. When defining a dimension_group, you can encapsulate multiple related dimensions, such as various time grains (year, month, day, etc.) or different representations of a duration. This offers a streamlined approach to managing related time or duration dimensions within your LookML model.

Using dimension_group not only simplifies the modeling of time-related data but also enhances usability in Looker, allowing analysts to easily explore data across different time perspectives without needing to define each dimension individually. The automatic generation of these dimensions based on the underlying date or time field makes it efficient for reporting and analysis.

In contrast, the other parameters do not provide the same functionality of grouping related time-based or duration dimensions:

• Dimension_set is not a valid LookML parameter.

• Timeframe_group is not recognized in LookML terminology.

• Duration_field is also not an officially designated parameter for defining groups of time or duration-based dimensions.

Thus, the dimension_group provides the necessary capability to effectively handle multiple time-based dimensions in a single cohesive construct.