Objects store instance-specific information as parameters. Since some object parameters are related, the relationship is captured in a dataset. A group of datasets that specifies some common parameters for the same object is called a datatable.

Datatables are made up of datasets for a specific type of component that can be applied to the component's descendents. For example, to indicate electrical resistance in a circuit diagram, you can define the Resistance parameter for a specific resistor. Because resistors are usually manufactured to a set resistance, you may need to constrain the resistance to a list of preferred values. You can also include the manufacturer's name and the material of which the resistor is made.

In the table below, each row defines a set of values for both manufacturer and material. Although you can specify carbon film as a material in two places, the parameters of each must be unique. Therefore, in this example, you cannot add another line that uses Philips and carbon film, but you can add a line using Philips and aluminum.

Each dataset in a datatable has a unique index. Use $$index$$ to specify the unique dataset index column in each dataset.

It is not mandatory to set a value for a parameter. A parameter that has no value is not applied to the object when the dataset is applied. Conversely, if a parameter is defined as unset, the parameter is applied to the object without assigning a value.

In the example below, a max temperature column is added to the resistor datatable. A value is defined for two manufacturers and left as unset for the third. When the Philips dataset is used, the max temperature parameter is unset. Conversely, when the Siemens dataset is used, the max temperature parameter is 300K.