column-primary-key-expression

Definition

Gets or sets columns to use as the key for the operation.

Example

context.BulkMerge(list, options => 
        options.ColumnPrimaryKeyExpression = entity => new { entity.Code1, entity.Code2 }
); 

Purpose

The ColumnPrimaryKeyExpression option let you choose a specific key to use to perform the bulk operations.

By example, when importing a file, you may have not have access to the ID but a unique Code instead.