When moving from an ERP system to another ERP system such as Microsoft Dynamics NAV, a lot of companies want to import their historical data into the new ERP. For example, the companies may want to import all the inventory entries made for the previous year for statistical purposes; or, if they start working with Microsoft Dynamics NAV in the middle of a fiscal year, they may want to import all the G/L entries made in the old system for the current fiscal year.

In Microsoft Dynamics NAV, this kind of data is stored in ledger entry tables. If you have to conduct a migration of such data, never import it directly into the ledger entry tables. Use journals instead, and post the data. This way, Microsoft Dynamics NAV will create the ledger entries for you in a consistent way.

For the item ledger entries, for instance, not only is the item ledger entry created, but the value, item register, item application entries, and other entries are created as well. If a journal is used, all these entries will consistently be created for us and we won't have to worry about anything.

Several journals exist in Microsoft Dynamics NAV. Choose the right journal for the ledger entries that have to be imported. If item ledger entries have to be imported, use the item journal. If G/L entries have to be imported, use the General Journal. Some journals use the same underlying table but have specific values in some fields or use specific fields to differentiate what they're used for. General Journals and Recurring Journals use the same Gen. Journal Line table, and item journals and revaluation journals use the same Item Journal Line table.

If you have to import data into these tables, make sure the right fields are being filled and that the right options are used.

A good idea would be to create some journal lines manually, through the interface provided by Microsoft Dynamics NAV, and compare these lines with the ones created through an import process. This way, we will know whether we are missing something in our import process code and will be able to correct it.