After objects are mapped for comparison and synchronization, you may encounter warnings on the Mapping page of the Data Comparison wizard. The warnings may be divided into two groups. They are table-level warnings and column level warnings.
Table-level warnings are displayed as Caution icon in the column with check boxes on the Mapping page of the Data Comparison wizard. Object pairs with table-level warnings are not compared. They are displayed with Caution icon instead of check box in the Data Comparison Document.
Actual document look may slightly vary from the above image depending on the product you use.
Column-level warnings are displayed as Caution icon in the Columns in Comparison column on the Mapping page of the Data Comparison wizard. They also appear in the Target column in the Column Mapping dialog box. Such warnings mean that some columns of a compared object pair cannot be compared because of type incompatibility or that you may encounter data loss when synchronizing data.
To read the warning messages, point to the warning icon. All warnings for this object will appear in the hint.
The following table contains information about table-level warnings and ways to remove them.
|No columns to compare||It means, there are no columns with the same name in this pair of tables (views). To compare them you should map the columns manually. For more information about the column mapping, see How to: Map Columns.|
|Objects to compare have no key column||It means that custom comparison key is used but is not set. You should mark at least one column pair as comparison key. For more information visit How to: Set Comparison Key.|