Calculation
Reference documentation for a Calculation object
Overview
A Calculation object provides a dynamic, calculated value in a Table in a Database Server. A calculation is a JavaScript function, which is always computed on-demand, whenever it is displayed or referenced in code. It can be added to the UI the same as any other Data Provider. A calculation is read-only
.
File Structure
The code for a Calculation is stored in a script file in a Solution directory -> "datasources" directory -> "table-name" directory. The file has the same name as the table "_calculation", with a .js
extension. For example, the products
table would have the calculation file products_calculation.js
.
Nesting file path: "solution/datasources/server-name/table-name/table-name_calculations.js"
Properties Summary
The following properties can be set for a Calculation object.
Properties Details
Name
The name of the calculation. It is also the same name as the function that returns the value.
Returned Type
The data type of the object that will be returned from the calculation. All data types are generalized to one of five standard types:
Code
This is the JavaScript function that defines the calculation. It takes no arguments and should return a value. Other data providers from this table, related data sources, and scope variables can be used.
Example
Stored
A calculation is said to be stored when a physical column with the same name exists on the table. The real column can be updated opportunistically when a calculation runs.
Stored calculations can be unpredictable, there is no guaranteed way to know exactly when they will run to update the underlying column in the table, especially if they are complex or depend on other calculations or methods.
A better approach is to use to catch changes to the table and make updates to other columns if necessary.
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