> For the complete documentation index, see [llms.txt](https://sharpsync.gitbook.io/sharpsync/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sharpsync.gitbook.io/sharpsync/fundamentals/property-mappings.md). # Property Mappings Property mappings are 1:1 or 1:N mappings from the source to the destination. Property Mappings define the BOM columns displayed in SharpSync. You can think of them as the mapping of meta data from one source to another source, or as the mapping of custom properties from one source to another source. For each mapping you create, a column will be displayed on the screen. Property mappings are expanded upon in detail here. After setting up your Property Mappings and Rules, open one of the Primary [Data Sources](/sharpsync/fundamentals/data-sources.md) to export the Bill Of Materials (BOM) to SharpSync. For more details on exporting a BOM, see the "Export Assembly Or Part" section for each Data Source. ### Property Mappings Table The following Property Mappings columns are visible by default:

Name	Description
Order	The order in which the columns appear in the Bill of Materials (double-click the cell to change the order)
Property Name	The name of the column as it appears in the Bill of Materials
Accessor	The unique internal name as it is used in SharpSync
Primary Data Source Property	The property as it is known at the primary source
Primary Data Source Type	The approximated type as it is known at the primary source
Update Primary Data Source	When checked, the primary source value will be updated
Secondary Data Source Property	The property as it is known at the secondary source
Secondary Data Source Type	The approximated type as it is known at the secondary source
Update Secondary Data Source	When checked, the secondary source value will be updated
Visible	Toggle Visibility Status
Read Only	Toggle Read Only Status
Settings	Click to edit the settings
Delete	Click to delete Property Mapping (Cannot Undo)
History	Shows a trimmed log of the changes to a specific mapping

Depending on your screen size, columns related to your Primary Data Source and Secondary Data Source might not all fit in the table. Use the scrollbar at the bottom, as shown in the screenshot below, to scroll other property mappings into view.

{% hint style="info" %} Important: You have to add at least 2 Data Sources before being able to successfully add Property Mappings. If any of your sources have changes applied (new properties added), come back to this screen and click the `UPDATE` button before you can select the new property. {% endhint %} ### Warnings in the mappings If you see orange borders around some property mappings it means that you've recently updated you mappings, and the mappings with warnings shown no longer exist. They were renamed or deleted. They don't exist in the source any more.