gis第二章下ppt課件(編輯修改稿)
2025-06-01 12:15 本頁面
【文章內容簡介】 tion 7601624 Smith John Lecturer Subject ID Subject Name Credit GEOG9240 Principles of GIS 3 Field Name Data Record University Record Record Student Record Staff Record Subject Record University Dept. Students Staff Subjects Efficient for wellstructured data. Search patterns are rigid. Difficult to share,modify, update. OnetoMany 最早出現(xiàn) ，IBM 公司IMS 2022年 12月 University Name China University of Geo Dept. Name No. of Professors No. of Support Staff No. of Students Geography 15 8 260 Student ID Last Name First Name Year 2178907 Ramos Je 1 Staff ID Last Name First Name Position 7601624 Smith John Lecturer Subject ID Subject Name Credit GEOG9240 Principles of GIS 3 Field Name Data Record University Record Dept. Record Student Record Staff Record Subject Record University Dept. Students Subjects Student ID Subject ID 2178907 GEOG9240 Registration Record Registration Staff Network Data Structure ManytoMany ?Flexible searches. ?Since all relationship are defined by pointers, the system of pointers is difficult to manage. ?Much memory can be required for the pointer information 2022年 12月 Staff ID Dept. Subject Name Credit Subject ID 7601624 Geography Principle of GIS 3 GEOG9240 8461912 Geography Remote Sensing 4 GEOG2021
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