Downloading from a Simple GoldSim Database

The following dialog is displayed when you specify a “Simple GoldSim Database” for the Data Source for an element and click on the Database tab in the properties dialog for a Data or Stochastic element (the two elements for which this type of data source can be specified):

As described in Appendix E of the GoldSim User’s Guide, the Simple GoldSim database has a specific structure in which a string in a field in one of the database tables must uniquely match the ID of the element you wish to link to.

When you link an element to a Simple GoldSim database, GoldSim locates the data to download within the database by using the element's ID and path. Unlike a Generic database, you do not need to manually indicate the record and field you wish to access from within GoldSim.

In addition, the units of data being downloaded are specified directly in the database, and need not be identified on the Database tab (although they must be consistent with the specified dimensions for the element as defined on the Definition tab).

Note: Particular care must be taken when importing Stochastics from a database, as different Stochastics could have different dimensions (e.g., a Binomial is always dimensionless; a Boolean is always a condition). If a Stochastic is defined in your model as a particular type of distribution whose output is inconsistent with that of the distribution that you are trying to import from the database, GoldSim will display an error.

Note: Care must also be taken when importing Stochastics that represent temperatures. This is because temperatures have an absolute reference (i.e., absolute zero). Differences between temperatures are expressed in ‘deg’ units (Cdeg, Fdeg). This can lead to errors when importing Stochastics, since GoldSim assumes a single unit for the distribution parameters, while some types of distributions would require two different types of units. For example, a Normal distribution representing a temperature would require the Mean to be specified in absolute units (e.g., C) and the Standard Deviation to be specified in difference units (e.g., Cdeg). If faced with this problem, there are several approaches for addressing this: 1) Use a distribution type where all parameters have the same units (e.g., triangular, uniform, cumulative); or 2) Specify and import the distributions as dimensionless and then apply a unit to the sampled value using an Expression element.

Because a Simple GoldSim database is so highly structured, if the database is properly defined, linking and downloading from it requires only two steps:

1. Select the appropriate data source from the Database drop-down list (all defined data sources will be listed).

GoldSim notes whether the download was successful (and, if successful, displays the date and time of the download).

The file SimpleDatabase.gsm in the General Examples/Database folder of your GoldSim directory (accessed by selecting File | Open Example... from the main menu) includes examples of how to download data from a Simple GoldSim database.