sco informix 里怎样使用detach

lmminlen

父进程打开了数据库,fork()后子进程,为什么不能操作数据库,停在哪里,据说要用detach ,怎么用呢?

liaosnet

detach 跟..............没看明白~~

lmminlen

也就是多进程怎么操作数据库.

ivhb

sqldetach ()
是个函数

lutabo

1. informix 自带例子.......................................
   
2. 
   
3. $INFORMIXDIR/demo/esqlc/sqldetach.ec
   
4. 
   
5. 
   
6. /****************************************************************************
   
7. *
   
8. *                               IBM INC.
   
9. *
   
10. *                           PROPRIETARY DATA
    
11. *
    
12. * Licensed Material - Property Of IBM
    
13. *
    
14. * "Restricted Materials of IBM"
    
15. *
    
16. * IBM Informix Client SDK
    
17. *
    
18. * (c)  Copyright IBM Corporation 2002. All rights reserved.
    
19. *
    
20. ****************************************************************************
    
21. */
    
22. 
    
23. main()
    
24. {
    
25.     EXEC SQL BEGIN DECLARE SECTION;
    
26.         mint pa;
    
27.     EXEC SQL END DECLARE SECTION;
    
28. 
    
29.     printf("SQLDETACH Sample ESQL Program running.\n\n");
    
30. 
    
31.     printf("Beginning execution of parent process.\n\n");
    
32.     printf("Connecting to default server...\n");
    
33.     EXEC SQL connect to default;
    
34.     chk("CONNECT");
    
35.     printf("\n");
    
36. 
    
37.     printf("Creating database 'aa'...\n");
    
38.     EXEC SQL create database aa;
    
39.     chk("CREATE DATABASE");
    
40.     printf("\n");
    
41. 
    
42.     printf("Creating table 'tab1'...\n");
    
43.     EXEC SQL create table tab1 (a integer);
    
44.     chk("CREATE TABLE");
    
45.     printf("\n");
    
46. 
    
47.     printf("Inserting 4 rows into 'tab1'...\n");
    
48.     EXEC SQL insert into tab1 values (1);
    
49.     chk("INSERT #1");
    
50.     EXEC SQL insert into tab1 values (2);
    
51.     chk("INSERT #2");
    
52.     EXEC SQL insert into tab1 values (3);
    
53.     chk("INSERT #3");
    
54.     EXEC SQL insert into tab1 values (4);
    
55.     chk("INSERT #4");
    
56.     printf("\n");
    
57. 
    
58.     printf("Selecting rows from 'tab1' table...\n");
    
59.     EXEC SQL declare c cursor for select * from tab1;
    
60.     chk("DECLARE");
    
61.     EXEC SQL open c;
    
62.     chk("OPEN");
    
63. 
    
64.     printf("\nForking child process...\n");
    
65.     fork_child();
    
66. 
    
67.     printf("\nFetching row from cursor 'c'...\n");
    
68.     EXEC SQL fetch c into $pa;
    
69.     chk("Parent FETCH");
    
70.     if (sqlca.sqlcode == 0)
    
71.         printf("Value selected from 'c' = %d.\n", pa);      
    
72.     printf("\n");
    
73. 
    
74.     printf("Cleaning up...\n");
    
75.     EXEC SQL close database;
    
76.     chk("CLOSE DATABASE");
    
77.     EXEC SQL drop database aa;
    
78.     chk("DROP DATABASE");
    
79.     EXEC SQL disconnect all;
    
80.     chk("DISCONNECT");
    
81. 
    
82.     printf("\nEnding execution of parent process.\n");
    
83.     printf("\nSQLDETACH Sample Program over.\n\n");
    
84. }
    
85. 
    
86. fork_child()
    
87. {
    
88.     mint rc, status, pid;
    
89. 
    
90.     EXEC SQL BEGIN DECLARE SECTION;
    
91.         mint cnt, ca;
    
92.     EXEC SQL END DECLARE SECTION;
    
93. 
    
94.     pid = fork();
    
95.     if (pid < 0)
    
96.         printf("can't fork child.\n");
    
97. 
    
98.     else if (pid == 0)
    
99.         {
    
100.         printf("\n**********************************************\n");
     
101.         printf("* Beginning execution of child process.\n");
     
102.         rc = sqldetach();
     
103.         printf("* sqldetach() call returns %d.\n", rc);
     
104. 
     
105.         /* Verify that the child is not longer using the parent's
     
106.          * connection and has not inherited the parent's connection
     
107.          * environment.
     
108.          */
     
109.         printf("* Trying to fetch row from cursor 'c'...\n");
     
110.         EXEC SQL fetch c into $ca;
     
111.         chk("* Child FETCH");
     
112.         if (sqlca.sqlcode == 0)
     
113.             printf("* Value from 'c' = %d.\n", ca);
     
114. 
     
115.         /* startup a connection for the child, since
     
116.          * it doesn't have one.
     
117.          */
     
118.         printf("\n* Establish a connection, since child doesn't have one\n");
     
119.         printf("* Connecting to database 'aa'...\n");
     
120.         EXEC SQL connect to 'aa';
     
121.         chk("* CONNECT");
     
122.         printf("* \n");
     
123. 
     
124.         printf("* Determining number of rows in 'tab1'...\n");
     
125.         EXEC SQL select count(*) into $cnt from tab1;
     
126.         chk("* SELECT");
     
127.         if (sqlca.sqlcode == 0)
     
128.             printf("* Number of entries in 'tab1' =  %d.\n", cnt);
     
129.         printf("* \n");
     
130. 
     
131.         printf("* Disconnecting from 'aa' database...\n");
     
132.         EXEC SQL disconnect current;
     
133.         chk("* DISCONNECT");
     
134.         printf("* \n");
     
135.         printf("* Ending execution of child process.\n");
     
136.         printf("**********************************************\n");
     
137.         
     
138.         exit();
     
139.         }
     
140. 
     
141.     /* wait for child process to finish */
     
142.     while ((rc = wait(&status)) != pid && rc != -1);
     
143. 
     
144. }
     
145. 
     
146. chk(s)
     
147. char *s;
     
148. {
     
149.     mint msglen;
     
150.     char buf1[200], buf2[200];
     
151. 
     
152.     if (SQLCODE == 0)
     
153.         {
     
154.         printf("%s was successful\n", s);
     
155.         return;
     
156.         }
     
157.     printf("\n%s:\n", s);
     
158.     if (SQLCODE)
     
159.         {
     
160.         printf("\tSQLCODE =  %6d: ", SQLCODE);
     
161.         rgetlmsg(SQLCODE, buf1, sizeof(buf1), &msglen);
     
162.         sprintf(buf2, buf1, sqlca.sqlerrm);
     
163.         printf(buf2);
     
164.         if (sqlca.sqlerrd[1])
     
165.             {
     
166.             printf("\tISAM Error =  %6hd: ", sqlca.sqlerrd[1]);
     
167.             rgetlmsg(sqlca.sqlerrd[1], buf1, sizeof(buf1), &msglen);
     
168.             sprintf(buf2, buf1, sqlca.sqlerrm);
     
169.             printf(buf2);
     
170.             }
     
171.         }
     
172. }

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