You can use Server.MapPath() to locate the access file in connectionString so that it searches in deployed location where application resides. Here main purpose is at runtime application should be able to locate the access data file.
code snnipet:
OledbConnection con= new OledbCOnnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+Server.MapPath("mydatabase.mdb")+";";
Please let us know whethe it helps you.