An input of document data, in which a rule for retrieving an object from a database has been specified for each region, is received. For each region, the number of times that the database is referenced for retrieving the object is counted by applying the rule. A reference value and each of the counted are compared. For each region, it is determined that the object is to be inserted in the region if the result of the comparison is that the number of times is less than or equal to the reference value, and that the object is not to be inserted in the region if the number of times is greater than the reference value. A preview of the document data is displayed with, for each region, the object being inserted in the region or the object not being inserted in the region in accordance with the determination.