# Value mappings

Abstract

Guide to how value mapping is used to map values from one object to another in the Sitecore Data Exchange Framework.

A value mapping controls the mapping of a single value from one object to another. The template for the generic value mapping is located at /sitecore/templates/DataExchange/Framework/DataAccess/Mapping/ValueMapping.

## Configuration

Field

Description

Source Accessor

The value accessor used to read the values to be mapped from the source object. (More precisely, the value reader assigned to the value accessor is used). If multiple value accessors are specified, the values read from the source object are added to a collection. This is used when the value writer expects multiple values (such as when the value writer represents a method).

When selected, even if only one source value accessor is specified, a collection is read (meaning a new collection is created and the value read is added to the collection). This option is used when the value writer expects a collection of values (such as when the value writer represents a method).

Target Accessor

The value accessor used to write the value to be mapped to the target object. (More precisely, the value writer assigned to the value accessor is used.)

Source Value Pre Transformer

The value reader used to convert the source object before the source accessor is used. The converted value becomes the source object within the context of this value mapping. This option is used when the source object must be converted into a different format before the source accessor can be used to read a value from it.

Source Value Transformer

The value reader used to convert the value read by the source accessor before the value is written to the target object. This option is used when the value read from the source object must be converted into a different format before the target accessor can be used to write the value to the target object.

Do Not Fail If Unable To Read Source Value

By default, this check box is not selected. If a value cannot be read from the source object, the data mapping process reports a failure.

If you select this check box, the value mapping does not fail - it simply does not run.

Ignore Null Values

This check box is selected by default. If a null value is read from the source object, the value mapping does not run. This prevents existing data from being overwritten.

If you clear this check box, the value mapping runs even if a null value is read from the source object.

Apply Mapping Rules

The apply mapping rules that determine whether the value mapping runs. All apply mapping rules specified here must pass in order for the value mapping to run. If one apply mapping rule fails, the value mapping does not run.

Mapping Set Fails If This Mapping Fails

By default, when a single value mapping fails, this does not result in the entire mapping process failing. If you select this check box, the entire mapping process fails if this particular value mapping fails.

Use this option when the value mapping is critical to the data mapping process. For example, if the value mapping specifies the way a primary key is set on the target object, it is not possible to update the target system without it. This is a critical error, so the entire mapping process must also fail.

## When to extend

You do not usually need to extend this component.