PHASE 1 o Data and codes are saved together o Data are not shared Programl Data 1 Program 2 Data 2 Program n Data n
PHASE 1 Data and codes are saved together Data are not shared 6 Program1 Data１ Program２ Data２ Program n Data n … …
Example Two C programs for finding the sum and maximum of 10 numbers *程序1：求10个数之和* *程序2：求10个数中的最大值* nclude <stdio.h≥ #include <stdio.h> main() main() int is=0; int is, inta[10={66,55,75,42,86,77,96,89,78,56 imta[10={66,55,75,42,86,77,96,89,78,56}; for(i=0i<10++) s=a则； s=s+a; fori=1i<10i++) printf%ds), if(s<a间)s=a]; printf%d"s)
Example：Two C programs for finding the sum and maximum of 10 numbers 7
PHASE 2 Codes and data for caluculation are separated Data are independent -Data are shared in terms of data files Program 1 Data file 1 File management Program 2 system Data file 2 Program n Data file n
PHASE 2 8 – Codes and data for caluculation are separated – Data are independent – Data are shared in terms of data files Data file１ … File management system Data file n Program１ Program２ Program n … Data file 2
o Previous example *程序3： *程序4： 文件C:Data.dat 求文件中10个数之和* 求文件中10个数的最大值* nclude<stdio.h≥ nclude <stdio.h≥ ®D.日回☒ main() main() 文件)编辑但) { 格式Q) 查看) int ix,s=0; int ix,s=-32767; FILE米p; FILE fp; 帮助) *打开文件* *打开文件* 66 fp=fopen("c:ata.dat",""), fp=fopen("c:ldata.dat","r"), 55 for(i=0i<10++) for(i=0i<10i++) 75 {*文件中读数据*树 {*文件中读数据* 42 fscanffp,"d fscanfifp,"%d"); 86 s=s+x, if(sx刘s=x; 77 } printf"%d",s), printf"%d",s); 89 fclose(p;*关闭文件* fclose(fp);*关闭文件*/ 56
Previous example 9
PHASE 3 Data are structured -Data are independent Data can be shared via DBMS - Nice user interface Maxium: SELECT Max(Num)FROM Data Average: SELECT Avg(Num)FROM Data 10
PHASE 3 10 – Data are structured – Data are independent – Data can be shared via DBMS – Nice user interface Maxium： SELECT Max(Num) FROM Data Average： SELECT Avg(Num) FROM Data