10 Appendix D Network Model al a3 b3 b4 b5 Figure D.14 Three set occurrences. 1.depositor,which has customer as the owner of the DBTG set,and account as the member of the DBTG set 2.account branch,which has branch as the owner of the DBTG set,and account as the member of the DBTG set The set depositor can be defined as follows: set name is depositor owner is customer member is account The set account branch can be defined similarly: set name is account _branch owner is branch member is account An instance of the database appears in Figure D.16.There are six set occur- rences listed next:three of set depositor (sets 1,2,and 3),and three of set account branch (sets 4,5,and 6). 1.Owner is customer record Hayes,with a single member account record A-102 2.Owner is customer record Johnson,with two member account records A-101 and A-201 3.Owner is customer record Turner,with three member account records A-305, A-402,andA-408. customer_name customer streef customer_city branch_name branch_city assets customer brancht depositor account branch account number balance account Figure D.15 Data-structure diagram.10 Appendix D Network Model Figure D.14 Three set occurrences. 1. depositor, which has customer as the owner of the DBTG set, and account as the member of the DBTG set 2. account branch, which has branch as the owner of the DBTG set, and account as the member of the DBTG set The set depositor can be defined as follows: set name is depositor owner is customer member is account The set account branch can be defined similarly: set name is account branch owner is branch member is account An instance of the database appears in Figure D.16. There are six set occur￾rences listed next: three of set depositor (sets 1, 2, and 3), and three of set account branch (sets 4, 5, and 6). 1. Owner is customerrecord Hayes, with a single member accountrecord A-102. 2. Owner is customer record Johnson, with two member account records A-101 and A-201. 3. Owner is customer record Turner, with three member account records A-305, A-402, and A-408. Figure D.15 Data-structure diagram