Map the fields.
a. Begin with standard fields that have direct equivalents between the systems. For example, Product Name, Price, and SKU. For fields in the source system that don’t have a standard equivalent in Salesforce, determine if there are existing custom fields that you can use or if you need to create new custom fields.
b. Map the custom fields. Make sure that equivalent fields exist in the target system or create them if necessary.
c. Identify fields that require data transformation. For example, combine first and last name fields into a full name field, and convert date formats. Document the transformation rules and logic in the mapping document.
d. Map complex relationships. Examine the relationships between records in the source data, such as parent-child links between products and categories or orders and customers. Ensure that these relationships are preserved in the target system by mapping the related fields correctly, such as lookup or main-detail fields in Salesforce. Plan the sequence of data loading to respect these relationships so that parent records are loaded before child records to maintain referential integrity.
e. Make sure that the Salesforce data types can accommodate the data from the source fields. For example, for text, number, date, and field lengths, adjust the data or the Salesforce fields as necessary.
f. Map default values.If the source system contains fields with default values that aren’t present in the data extract, specify these default values in the mapping document.
g. Ensure that picklist and multi-select fields in the source system have equivalent values in Salesforce. Map or transform values as needed to fit the Salesforce environment.
h. Handle unique identifiers. If the target system requires matching external IDs, map these fields to ensure that the data is included in the migration. Establish a method for generating new unique identifiers if they can’t be preserved or if the target system generates new ones upon data import.
i. Set default values and null handling. Decide if empty or null source fields can be set to default values in the target system or left blank. Document the default values for fields that require them in the target system.