It is highly recommended you use the MerchantList feed in conjuntion with the Codes and Offers feeds otherwise it is likely that you will not accurately match up the codes / offers to the merchants you have in your own database.
Use the ICIDs to match up data. (Recommended)
The ICIDs are the iCodes unique identifiers for the Types.. merchants, codes, offers, these IDs never change and are unique to either the code, offer or merchant globally throughout our API. (Always check against the Type as a code or offer may share the same ICID, but two codes will never share the same ICID and nor will two offers or merchants) - *Due to a later addition of the Merchants ICID added to the codes and offers feeds, the Merchants ICID is named the MID so not to clash with the codes/offers ICIDs.
Do NOT use the networks merchant id to match up data. (Not Recommended)
The merchant id's are only unique to the network and the same ID can be shared on other networks so not much use to use to match up data, also amazon and ebay will not have merchant IDs as they are not networks, and so do not need to give their own programme an ID.
Do NOT use the merchant name to match up data. (Not Recommended)
The merchant name is certainly not recommended to match up data because a merchant may re-brand, or the formatting of the merchant name maybe altered for various reasons and so cannot be relied upon as a unique identifier.