1. A method of storing chemical structure data in a storage device and searching said chemical structure data using a query chemical structure by examining the match or analogy between the said query structure with the structure data stored, which comprises: assigning numbers to each chemical unit, which can be either an atom of a specific or generic element, or a generic group of atoms, of each structure to be stored, and storing the numbers of chemical units to which the said chemical unit is chemically connected in a connection table, and storing the attribute data, which describe the chemical characteristics of the said chemical unit, in an attribute table; then assigning numbers to each chemical unit, which can be either an atom of a specific or generic element, or a generic group of atoms, of the query chemical structure to be used to search the stored chemical structure data, and storing the numbers of chemical units to which the said chemical unit is chemically connected in a connection table, and storing the attribute data, which describe the chemical characteristics of the said chemical unit, in an attribute table, and then examining the match or analogy of the query structure and each stored chemical structure by comparing chemical units of the query chemical structure with the chemical units of the stored chemical structure by matching the attributes of the chemical unit of the stored chemical structure and the attributes of the corresponding chemical units of the query structure according to a mathematical condition defined in advance, either with or without matching the specific or generic element type of the chemical unit of the stored chemical structure and the specific or generic element type of the chemical unit of the query chemical structure.