2. The method of claim 1 , wherein the first relational data includes data identifying the relationship between the first sale item and the second sale item, and the method further comprises: juxtaposing and configuring for display on a user terminal the reference data of the first sale item and relational data identifying the second sale item, the relational data being associated with the reference data of the first sale item and identifying the relationship between the first sale item and the second sale item.
2. The method of claim 1 , wherein the first relational data includes data identifying the relationship between the first sale item and the second sale item, and the method further comprises: juxtaposing and configuring for display on a user terminal the reference data of the first sale item and relational data identifying the second sale item, the relational data being associated with the reference data of the first sale item and identifying the relationship between the first sale item and the second sale item. 6. The method according to claim 2 , wherein the relational data is configured to be displayed by the user terminal in an order according to the relationship between the first sale item and the second sale item.