If a client uploads valid classification data to SiteCatalyst, the integration automatically downloads that classification data and use it as product meta-data in the relational table. Each classification field is stored in the integration's relational table with a prefix of "Classification". For example, if a shoe company had two fields in their classification data "Style" and "Color", those fields would be stored in the relational table as "Classification Style" and "Classification Color".
If a client corrupts classification data (ex. Duplicate keys) the integration continues to work, but with only the standard relational table fields. Importing Classifications are disabled for these clients.