When copying content, source columns can be remapped with different destination columns, even if they have a different field type.
- To set up those mappings, click on Map properties (the Property mappings window can also be opened from the property template).
- In the Property mappings window, the list of source properties is displayed on the left and mapped properties are displayed on the right.
The source properties are all the columns defined in source list or library, while the destination properties are all the columns that are available in the destination list or library. The system properties are not displayed in the list of destination properties since they are not writeable, they will automatically be handled depending on the options you choose for the copy.
By default, all properties with the same value are automatically mapped. To change a mapping or to create a new one, simply drag and drop properties from the list of source properties to the right pane. Make sure to drop them next to the desired destination properties.
Once saved, these mappings will be applied during the copy. The value in the source property will be copied to the destination property. A colored indicator will display whether a property is mapped or not. Red means that it isn’t mapped while green means that it is.
Note that you can’t add fields to your lists or libraries from this window. It simply displays what is available in SharePoint. If you want more properties to appear in this window, you will need to add columns to your SharePoint list or library.
If a destination column allows for multiple values, you will be able to merge multiple columns into one during the migration. For example, two choice columns from the source list can be merged to a managed metadata column that allows multiple values in the destination list (assuming the values exist in the term set used by the managed metadata column).
When copying list items, there is no implicit way to determine if the item being copied already exists at the destination. For documents, two files with the same filename value in the same folder are implicitly the same file, but this is not always true for list items. For example, a list item can be a meeting and two meetings can have a title "Team meeting" but they can be on different dates, and so they can be different items.
By default, Sharegate will always try to determine the best keys for your list. However, to make sure that items that already exist on the destination are correctly overwritten when necessary, you should define the key properties yourself. You can do so by clicking on the key icon besides the property mapping.
Items that have the same value for all the key properties will be considered the same item and you can make sure that you won’t have duplicate items if you copy the same source item(s) more than once.
From the Property Template
The Property mappings window can also be opened from the template selection window or from the property template window.