---
title: "Expression functions mapping"
slug: "bc-expression-functions-mapping"
tags: ["BC", "BIS", "Business Central", "Business Integration Solutions", "Concept", "Task"]
updated: 2026-06-25T09:59:07Z
published: 2026-06-25T09:59:07Z
canonical: "docs.staedean.com/bc-expression-functions-mapping"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.staedean.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Expression functions mapping

With function expression-to-field mapping, you can run a function from Microsoft Dynamics 365 Business Central to calculate values.

## Usage

Use an expression function when you want to manipulate, calculate, or enrich the data being imported or exported. You can use the **Expression Wizard** to map the arguments of a function with appropriate values. You can use expression functions both when importing and when exporting data from Microsoft Dynamics 365 Business Central.

## Concept

An expression function calls Microsoft Dynamics 365 Business Central functions during mapping. Each function can have its own set of arguments. These functions are available to users via expressions. There is virtually no limit on how often you can use a function in a single expression.

```plaintext
Codeunit:11070243.XUPPERCASE(Codeunit:11070243.XLOWERCASE(Codeunit:11070243.XUPPERCASE(Codeunit:11070243.XCOMPANYNAME())))
```

## Registering

To use functions in the **Expression Wizard**, register the functions in the Function Library. This is explained in [Expression function](/business-central/docs/bc-expression-function). The function library contains the collection of standard functions and you can easily extend it with custom functions.

## Standard expression functions

Business Integration Solutions includes standard functions. Some products may add their own additional set. These are registered during product installation.

For a list of all standard functions, see [Expression function](/business-central/docs/bc-expression-function).

## Related

- [Expression function](/bc-expression-function.md)
- [Function list](/bc-function-list.md)
- [Create a custom codeunit with expression functions](/bc-create-a-custom-codeunit-with-expression-functions.md)
- [Expose functions to the Function interface](/bc-expose-functions-to-the-function-interface.md)
- [Create a custom codeunit with expression functions using the Namespaced Invokable interface](/bc-create-custom-codeunit-expression-functions-namespaced-invokable-interface.md)
- [Create a custom codeunit with expression functions using the Invokable0 to Invokable10 interface](/create-custom-codeunit-expression-functions-using-invokable0-to-invokable10-inte.md)
- [Mapping](/bc-bis-mapping.md)
- [Request extension point in STAEDEAN - Business Central software](/bc-how-to-request-an-extension-point-in-staedean-software.md)