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linux下mysql函数的详细案列

1 MYSQL  *    STDCALL mysql_real_connect(MYSQL *mysql, const char *host,
2                                            const char *user,
3                                            const char *passwd,
4                                            unsigned int port,
5                                            const char *unix_socket,
6                                            unsigned int clientflag);

1. 如何连接数据mysql数据库...。

[gxjun@localhost Mysql]$ cat demo.c

 1 //connect to mysql
 2 #include<stdio.h>
 3 #include"mysql.h"
 4                                                                                                                                                                                                 
 5 int main (void)
 6 {                                                                                                                                                                                               
 7   MYSQL mysql;                  //need a instance to init
 8                                                                                                                                                                                                 
 9   int t, r;                     //connect the database
10                                                                                                                                                                                                 
11   mysql_init (&mysql);
12                                                                                                                                                                                                 
13   if (!mysql_real_connect
14       (&mysql, "localhost", "root", "123", "demo", 0, NULL, 0))
15     {
16       printf ("Error connecting to database:%s
", mysql_error (&mysql));
17     }
18   else
19     {
20       printf ("Connected MYSQL successfully!
");
21     }
22   mysql_close (&mysql);
23   return 0;
24 }
25 
26

2.关于make文件的内容：

[gxjun@localhost Mysql]$ cat demo.mk

 1 .SUFFIXES: .o .c
 2                                                                                                                                                                                                
 3 CC = gcc
 4 SRC = demo.c
 5 OBJS = $(SRC : .c = .o)
 6 EXEC = demo
 7                                                                                                                                                                                                
 8 .PHONY: start
 9                                                                                                                                                                                                
10 start: $(OBJS)
11 
12         $(CC)   -o $(EXEC) $(OBJS)    -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
13 
14 $(OBJS): $(SRC)
15 
16         $(CC)  -g  -Wall $(OBJS) -c $(SRC)  #-I/usr/include/mysql  -L/usr/lib/mysql  -lmysqlclient
17  
18 .PHONY: clean
19 
20 clean:
21          rm -f $(OBJS)
22

几点说明，对于MYSQL数据库程序进行编译，无法像编译普通程序那样，而是要制定include路径，库文件路径和链接模块mysqlclient , 在某些系统上，可能还要用-lz选项链接压缩库。假设MYSQL的头文件在、usr/include/mysql 路径下，库文件在/usr/lib/mysql 路径下，则执行如下命令

-I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient

3. 进行make编译： make -f demo.mk

二：数据查询函数

[gxjun@localhost demo1]$ cat query.c
//select.c

 1 #include<stdio.h>
 2 #include"mysql.h"
 3 
 4 int main (void)
 5 {
 6 
 7   MYSQL mysql;
 8   MYSQL_RES *res;
 9   MYSQL_ROW row;
10   char *query;
11   int flag, t;                  //connect the database
12 
13   mysql_init (&mysql);
14   if (!mysql_real_connect
15       (&mysql, "localhost", "root", "123", "demo", 0, NULL, 0))
16     {
17       printf ("Failed to connect to Mysql! 
");
18       return 0;
19     }
20   else
21     {
22       printf ("Connected MySQL successfully!
");
23       query = "select * from student";
24       flag = mysql_real_query (&mysql, query, (unsigned int) strlen (query));
25       if (flag)
26         {
27           printf ("query failed ! 
");
28           return 0;
29         }
30       else
31         {
32           printf ("[ %s ] made...
", query);
33         }
34       res = mysql_store_result (&mysql);
35       while (row = mysql_fetch_row (res))
36         {
37           for (t = 0; t < mysql_num_fields (res); t++)
38             printf ("%s  ", row[t]);
39           printf ("
");
40         }
41       mysql_close (&mysql);
42       return 0;
43     }
44 
45   return 0;
46 }

函数关于Mysql查询语句：

（1） int STDCALL mysql_query(MYSQL *mysql, const char *q);

（2） int STDCALL mysql_real_query(MYSQL *mysql, const char *q, unsigned int length);

关于这两个函数，使用较多的为（2）式

//makefile文件....

[gxjun@localhost demo1]$ cat query.mk

 1 .SUFFIXES: .o .c
 2 CC = gcc
 3 SRC = query.c
 4 OBJS = $(SRC: .c = .o)
 5 EXEC = Demo
 6 CLS = rm
 7 
 8 .PHONY: start
 9 
10 start: $(OBJS)
11 
12         $(CC) -o $(EXEC)   $(OBJS) -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
13 
14 $(OBJS): $(SRC)
15 
16         $(CC) -g -Wall $(OBJS) -c $(SRC)   -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
17 .PHONY: clean
18 clean:
19         $(CLS) -f $(OBJS)

关于bash 语言：

[gxjun@localhost demo1]$ cat query.sh

    indent -gnu query.c

          echo "make is running ....!"

          make -f query.mk

          echo "make is stopping ....! "

使用关于nm 查看想要看的函数；

[gxjun@localhost demo1]$ nm Demo

08049aac A __bss_start
080485d0 t call_gmon_start
08049aac b completed.1
08049a64 d __CTOR_END__
08049a60 d __CTOR_LIST__
08049984 D __data_start
08049984 W data_start
08048864 t __do_global_ctors_aux
080485f4 t __do_global_dtors_aux
08049988 D __dso_handle
08049a6c d __DTOR_END__
08049a68 d __DTOR_LIST__
08049990 A _DYNAMIC
08049aac A _edata
08048980 r __EH_FRAME_BEGIN__
08049ab0 A _end
08048888 T _fini
08049984 A __fini_array_end
08049984 A __fini_array_start
080488c0 R _fp_hw
08048630 t frame_dummy
08048980 r __FRAME_END__
08049a74 A _GLOBAL_OFFSET_TABLE_
         w __gmon_start__
080484e4 T _init
08049984 A __init_array_end
08049984 A __init_array_start
080488c4 R _IO_stdin_used
08049a70 d __JCR_END__
08049a70 d __JCR_LIST__
         w _Jv_RegisterClasses
08048830 T __libc_csu_fini
08048800 T __libc_csu_init
         U __libc_start_main@@GLIBC_2.0
0804865c T main
         U mysql_close
         U mysql_fetch_row
         U mysql_init
         U mysql_num_fields
         U mysql_real_connect
         U mysql_real_query
         U mysql_store_result
0804998c d p.0
         U printf@@GLIBC_2.0
080485ac T _start
         U strlen@@GLIBC_2.0

我们想要查询的表单：

mysql> select * from student
-> ;
+------+-------+
| sno | sname |
+------+-------+
| 1001 | jim |
+------+-------+
1 row in set (0.05 sec)

关于MYSQL函数查询结果:

[gxjun@localhost demo1]$ ./Demo

Connected MySQL successfully!
[ select * from student ] made...
1001 jim

---------------------------------------------华丽丽的分割线-----------------------------------------------------

关于数据库的插入和查询以及连接的综合案列：

[gxjun@localhost demo2]$ cat adddata.c

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stdlib.h>
 4 #include "mysql.h"
 5 //#include<fcntl.h>
 6 
 7 int
 8 main (void)
 9 {
10 
11   MYSQL mysql;                  //var mysql
12   MYSQL_RES *res;               //grep_result
13   MYSQL_ROW row;                //mysql_row
14   int r;                        //var_tmp  r
15   char *query[4];
16   int flag;
17   //init_mysql
18   mysql_init (&mysql);
19   if (!mysql_real_connect
20       (&mysql, "localhost", "root", "123", "demo", 0, NULL, 0))
21     {
22 
23       printf ("can't connect the mysql ! errInfo=[%s]", mysql_error (&mysql));
24 
25     }
26   else
27     {
28       printf ("connect the mysql successfully!");
29       query[0] = "insert into student(sno,sname)values(1002,'tom')";
30       query[1] = "insert into student(sno,sname)values(1003,'gongxijun')";
31       query[2] = "insert into student(sno,sname)values(1004,'qinshihuang')";
32 //insert data to mysql
33       for (r = 0; r < 3; r++)
34         {
35           if (mysql_real_query
36               (&mysql, query[r], (unsigned int) strlen (query[r])))
37             {
38               printf ("insert data[%d] is failed !
", r);
39               return 0;
40             }
41           else
42             {
43               printf ("Insert data[%d] is successfully !
", r);
44             }
45         }
46     }
47 
48 //query part
49   query[3] = "select * from student";
50   flag =
51     mysql_real_query (&mysql, query[3], (unsigned int) strlen (query[3]));
52   if (!flag)
53     {
54       res = mysql_store_result (&mysql);
55       while (row = mysql_fetch_row (res))
56         {
57           for (r = 0; r < mysql_num_fields (res); r++)
58             {
59               printf ("%s ", row[r]);
60             }
61           printf ("
");
62         }
63     }
64   else
65     {
66       printf ("query failed !
");
67       return 0;
68 
69     }
70   mysql_close (&mysql);
71   return 0;
72 }
73

//关于makefile文件：

[gxjun@localhost demo2]$ cat adddata.mk

 1 .SUFFIXES: .o .c
 2 CC = gcc
 3 SRC = adddata.c
 4 OBJS = $(SRC: .c = .o)
 5 EXEC = Demo
 6 
 7 .PHONY: start
 8 start: $(OBJS)
 9 
10         $(CC) -o $(EXEC) $(OBJS) -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
11 
12 $(OBJS): $(SRC)
13 
14         $(CC) -g  -Wall $(OBJS) -c $(SRC)  -I/usr/include/mysql -L/usr/lib/mysql -lmysqlcilent
15 
16 .PHONY: clean
17 
18 clean:
19         rm -f $(OBJS) core.*
20 
21

//关于shell文件

[gxjun@localhost demo2]$ cat adddata.sh

1 #!/bin/bash/
2 
3 echo "make is starting ....!"
4 indent -gnu adddata.c
5 
6 make -f adddata.mk
7 echo "make is endding ...! "
8 
9

显示结果：

[gxjun@localhost demo2]$ ./Demo
connect the mysql successfully!Insert data[0] is successfully !
Insert data[1] is successfully !
Insert data[2] is successfully !
1001 jim
1002 tom
1003 gongxijun
1004 qinshihuang
[gxjun@localhost demo2]$ ls

关于数据库的插入和查询以及连接的综合案列：

[gxjun@localhost demo2]$ cat adddata.c

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stdlib.h>
 4 #include "mysql.h"
 5 //#include<fcntl.h>
 6 
 7 int
 8 main (void)
 9 {
10 
11   MYSQL mysql;                  //var mysql
12   MYSQL_RES *res;               //grep_result
13   MYSQL_ROW row;                //mysql_row
14   int r;                        //var_tmp  r
15   char *query[4];
16   int flag;
17   //init_mysql
18   mysql_init (&mysql);
19   if (!mysql_real_connect
20       (&mysql, "localhost", "root", "123", "demo", 0, NULL, 0))
21     {
22 
23       printf ("can't connect the mysql ! errInfo=[%s]", mysql_error (&mysql));
24 
25     }
26   else
27     {
28       printf ("connect the mysql successfully!");
29       query[0] = "insert into student(sno,sname)values(1002,'tom')";
30       query[1] = "insert into student(sno,sname)values(1003,'gongxijun')";
31       query[2] = "insert into student(sno,sname)values(1004,'qinshihuang')";
32 //insert data to mysql
33       for (r = 0; r < 3; r++)
34         {
35           if (mysql_real_query
36               (&mysql, query[r], (unsigned int) strlen (query[r])))
37             {
38               printf ("insert data[%d] is failed !
", r);
39               return 0;
40             }
41           else
42             {
43               printf ("Insert data[%d] is successfully !
", r);
44             }
45         }
46     }
47 
48 //query part
49   query[3] = "select * from student";
50   flag =
51     mysql_real_query (&mysql, query[3], (unsigned int) strlen (query[3]));
52   if (!flag)
53     {
54       res = mysql_store_result (&mysql);
55       while (row = mysql_fetch_row (res))
56         {
57           for (r = 0; r < mysql_num_fields (res); r++)
58             {
59               printf ("%s ", row[r]);
60             }
61           printf ("
");
62         }
63     }
64   else
65     {
66       printf ("query failed !
");
67       return 0;
68 
69     }
70   mysql_close (&mysql);
71   return 0;
72 }
73

//关于makefile文件：

[gxjun@localhost demo2]$ cat adddata.mk

 1 .SUFFIXES: .o .c
 2 CC = gcc
 3 SRC = adddata.c
 4 OBJS = $(SRC: .c = .o)
 5 EXEC = Demo
 6 
 7 .PHONY: start
 8 start: $(OBJS)
 9 
10         $(CC) -o $(EXEC) $(OBJS) -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
11 
12 $(OBJS): $(SRC)
13 
14         $(CC) -g  -Wall $(OBJS) -c $(SRC)  -I/usr/include/mysql -L/usr/lib/mysql -lmysqlcilent
15 
16 .PHONY: clean
17 
18 clean:
19         rm -f $(OBJS) core.*

//关于shell文件

[gxjun@localhost demo2]$ cat adddata.sh

1 #!/bin/bash/
2 
3 echo "make is starting ....!"
4 indent -gnu adddata.c
5 
6 make -f adddata.mk
7 echo "make is endding ...! "
8

显示结果：

-------------------------------------华丽丽的分割线-----------------------------------------------------------

|++++++++++++++++++++++显示删除和查询功能++++++++++++++++++++++++++++++++++++|

del.c代码：

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include "mysql.h"
 4 
 5 int
 6 main (void)
 7 {
 8 
 9   MYSQL mysql;
10 
11   MYSQL_RES *res;
12 
13   MYSQL_ROW row;
14   char *query;
15   int rr, flag;
16   mysql_init (&mysql);          //init mysql
17   MYSQL *pts = mysql_real_connect (&mysql, "localhost", "root", "123", "demo", 0, NULL, 0);     //to connect the mysql
18   if (pts == NULL)
19     {
20       printf ("connect is failed !  [%s ]
", mysql_error (&mysql));
21       return 0;
22     }
23   printf ("conected successfully ! 
");
24 //the part of function is to query the data of mysql
25 
26   query = "select * from student ";
27 
28   flag = mysql_real_query (&mysql, query, (unsigned int) strlen (query));
29   if (flag)
30     {
31       printf ("query the mysql is failed ! [%s ] 
", mysql_error (&mysql));
32       return 0;
33     }
34 
35   res = mysql_store_result (&mysql);    // return a point of res (var MYSQL_RES *)
36 
37   while (row = mysql_fetch_row (res))
38     {                           //to next row
39 
40       for (rr = 0; rr < mysql_num_fields (res); rr++)
41         printf ("[ %s ] ", row[rr]);
42       puts ("");
43     }
44   //the part of del the data  of mysql
45   query = "delete from student where sname = 'gongxijun'";
46   flag = mysql_real_query (&mysql, query, (unsigned int) strlen (query));
47   if (flag)
48     {
49       printf ("sorry ,delect the data of mysql is failed !
 [%s ] ",
50               mysql_error (&mysql));
51       return 0;
52     }
53   //query again
54   query = "select * from student ";
55   flag = mysql_real_query (&mysql, query, (unsigned int) strlen (query));
56   if (flag)
57     {
58       printf ("query failed ! the result= [%s ] 
", mysql_error (&mysql));
59       return 0;
60     }
61   res = mysql_store_result (&mysql);
62   while (row = mysql_fetch_row (res))
63     {
64       for (rr = 0; rr < mysql_num_fields (res); rr++)
65         printf ("[%s ]
", row[rr]);
66       printf ("
");
67     }
68   mysql_close (&mysql);         //close mysql
69   return 0;
70 }
71

关于makefile文件： del.mk

 1   .SUFFIXES: .o .c
 2 CC = gcc
 3 SRC = del.c
 4 OBJS = $(SRC: .c =.o)
 5 EXEC = Demo
 6                                                                                                                                                   
 7 .PHONY: start
 8 start: $(OBJS)
 9                                                                                                                                                   
10         $(CC) -o $(EXEC) $(OBJS) -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
11                                                                                                                                                   
12 $(OBJS): $(SRC)
13                                                                                                                                                   
14         $(CC) -g -Wall $(OBJS) -c  $(SRC) -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
15                                                                                                                                                   
16 .PHONY: clean
17 clean:
18         rm -f $(OBJS) core.*
19                                                                                                                                                   
20 ~
21 ~

关于bash文件：

indent -gnu del.c

make -f del.mk
显示结果：
[gxjun@localhost demo3]$ bash del.sh
bash: /root/.bashrc: 权限不够
make: Circular del.c <- del.c dependency dropped.
gcc -o Demo del.c -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
[gxjun@localhost demo3]$ ./Demo
conected successfully !
[ 1001 ] [ jim ]
[ 1002 ] [ tom ]
[ 1003 ] [ gongxijun ]
[ 1004 ] [ qinshihuang ]
sorry ,delect the data of mysql is failed !
[You have an error in your SQL syntax near '* from student where sname =gongxijun' at line 1 ] [gxjun@localhost demo3]$ vi del.c
[gxjun@localhost demo3]$ bash del.sh
bash: /root/.bashrc: 权限不够
make: Circular del.c <- del.c dependency dropped.
gcc -o Demo del.c -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
[gxjun@localhost demo3]$ ./Demo
conected successfully !
[ 1001 ] [ jim ]
[ 1002 ] [ tom ]
[ 1003 ] [ gongxijun ]
[ 1004 ] [ qinshihuang ]
sorry ,delect the data of mysql is failed !
[Unknown column 'gongxijun' in 'where clause' ] [gxjun@localhost demo3]$
[gxjun@localhost demo3]$
[gxjun@localhost demo3]$ vi del.c
[gxjun@localhost demo3]$ bash del.sh
bash: /root/.bashrc: 权限不够
make: Circular del.c <- del.c dependency dropped.
gcc -o Demo del.c -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
[gxjun@localhost demo3]$ ./Demo
conected successfully !
[ 1001 ] [ jim ]
[ 1002 ] [ tom ]
[ 1003 ] [ gongxijun ]
[ 1004 ] [ qinshihuang ]
[1001 ]
[jim ]

[1002 ]
[tom ]

[1004 ]
[qinshihuang ]

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原文地址：https://www.cnblogs.com/gongxijun/p/4554507.html

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