Data Entry Form - repost

I am looking for a data entry form and a database. The data base will have two tables. A Lead Table and an Event Table. Each Lead table can have multiple event records. One or Two phone numbers will act as the "key" to the tables. Phone is format ###-###-####. We can enter one phone number and it would locate and match against TWO phones stored in the database. We need the ability to import data to the database. The import file must match the format specified by the software. If a phone number being imported matches a phone number already on file then the event table is checked to see if the event date already exists. If not then a new Event record is created for that Lead record. If an event record date already exists for that lead record then nothing is updated. It is important that since data entry will be done online with perhaps slow internet connects that the form have no graphics so the data entry person does not have to wait for page loads. AJAX might event be used to minimize page loads.