作者： zieckey ( zieckey@yahoo.com.cn )
All Rights Reserved
现在我们来写个C/C++程序，
调用 sqlite 的 API 接口
函数查询e
数据库中表的
内容。
下面是一个C程序的例子，
显示怎么使用
sqlite 的 C/C++ 接口. 这个
函数调用sqlite3_open() 在 22 行打开
数据库,
sqlite3_get_table 在 40 行执行
sql 命令,并且
sqlite3_close() 在 47 行
关闭数据库连接。
代码:
// name： query_test_1.c
// This file is used to test C/C++ API for
sqlite
// Author : zieckey
// 2006/06/28
#include <st
dio.h>
#include <
sqlite3.h>
int main( void )
{
sqlite3 *db=NULL;
char *zErrMsg = 0;
int nrow = 0,ncolumn = 0;
char **azResult; //二维数组存放结果
int rc;
rc =
sqlite3_open("zieckey.db",&db); //打开指定的
数据库文件,如果不存在将创建一个同名的
数据库文件
if( rc ){
fprintf(stderr,"Can't open database: %s/n",
sqlite3_errmsg(db));
sqlite3_close(db);
exit(1);
}
else printf("open zieckey.db successfully!/n");
//也可以参考 sprintf 的
用法
//char *
sql = "SELECT SensorParameter FROM SensorData WHERE SensorID = 1";
char *
sql = "SELECT * FROM SensorData ";
/*
int
sqlite3_get_table(
sqlite3*,const char *
sql,char***resultp,int *nrow,int *ncolumn,char **errmsg);
result中是以数组的形式存放你所
查询的数据，首先是表名，再是数据。nrow,ncolumn分别为
查询语句返回的结果集的行数，列数，没有查到返回0
*/
sqlite3_get_table(db,
sql,&azResult,&nrow,&ncolumn,&zErrMsg);
int i=0;
for(i=0;i<100;i++)
printf("%s/n",azResult[i]);
printf("row:%d column=%d /n",nrow,ncolumn);
printf("zErrMsg = %s /n",zErrMsg);
sqlite3_close(db); //
关闭数据库
return 0;
}
编译：# gcc query_test_1.c -o db.out
也许会碰到类似这样的问题：
query_test_1.c:2:21:
sqlite3.h: No such file or directory
query_test_1.c: In function `main':
query_test_1.c:6: error: `
sqlite3' undeclared (first use in this function)
query_test_1.c:6: error: (Each undeclared identifier is reported only once
query_test_1.c:6: error: for each function it appears in.)
query_test_1.c:6: error: `db' undeclared (first use in this function)
这是个没有找到库
文件的问题。
由于用到了
用户自己的库
文件,所用应该指明所用到的库，我们可以这样编译：
# gcc query_test_1.c -o db.out -l
sqlite3
我用用 -l
sqlite3 选项就可以了(前面我们
生成的库
文件是 lib
sqlite3.so.0.8.6 等,
去掉前面的lib和后面的版本标志,就剩下
sqlite3 了所以是 -l
sqlite3 )。
如果我们在编译安装的时候，选择了安装路径，例如这样的话：
.......
# ../
sqlite/configure --prefix=/usr/local/arm-linux/
sqlite-ix86-linux
.......
这样编译安装时，
sqlite的库
文件将会
生成在 /usr/local/arm-linux/
sqlite-ix86-linux/lib 目录下
这时编译还要指定库
文件路径，因为系统默认的路径没有包含 /usr/local/arm-linux/
sqlite-ix86-linux/lib
# gcc query_test_1.c -l
sqlite3 -L/usr/local/arm-linux/
sqlite-ix86-linux/lib
如果还不行的话，可能还需要指定头
文件 sqlite3.h 的路径，如下：
# gcc query_test_1.c -l
sqlite3 -L/usr/local/arm-linux/
sqlite-ix86-linux/lib -I/usr/local/arm-linux/
sqlite-ix86-linux/include
这样编译应该就可以了 ，运行：
# ./db.out
./db.out: error while loading shared libraries: lib
sqlite3.so.0: cannot open shared object
file: No such file or directory 运行是也许会出现类似上面的
错误。 这个问题是由于运行沿着系统默认路径没有找到库
文件引起的。这时需要指定 lib
sqlite3.so.0 库
文件的路径。 在shell下输入： export LD_LIBRARY_PATH=/usr/local/arm-linux/
sqlite-ix86-linux/lib:$LD_LIBRARY_PATH 再运行 # ./db.out open colliery.db successfully! ID SensorID SiteNum Time SensorParameter 1 1 1 200605011206 18.9 2 1 1 200605011306 16.4 3 1 1 200605011406 15.3 4 1 1 200605011506 15.5 5 1 1 200605011606 15.8 6 1 1 200605011706 12.5 7 1 1 200605011806 5.8 8 8 5 200605011206 7 9 8 5 200605011306 6 10 8 5 200605011406 5 11 8 5 200605011506 6 12 8 5 200605011606 5 13 8 5 200605011706 6 14 8 5 200605011806 7 17 5 4 200605010606 21.6 18 5 4 200605010706 21.5 19 5 4 200605010806 21.2 20 5 4 200605010906 21.3 21 5 4 200605011006 21.6 row:51 column=5 zErrMsg = (null) 在shell命令行下用同样的命令，可以看到一下
内容。这里可以比较一下，不难得到一些有价值的信息。
sqlite> SELECT * FROM SensorData ; 1|1|1|200605011206|18.9 2|1|1|200605011306|16.4 3|1|1|200605011406|15.3 4|1|1|200605011506|15.5 5|1|1|200605011606|15.8 6|1|1|200605011706|12.5 7|1|1|200605011806|5.8 8|8|5|200605011206|7 9|8|5|200605011306|6 10|8|5|200605011406|5 11|8|5|200605011506|6 12|8|5|200605011606|5 13|8|5|200605011706|6 14|8|5|200605011806|7 17|5|4|200605010606|21.6 18|5|4|200605010706|21.5 19|5|4|200605010806|21.2 20|5|4|200605010906|21.3 21|5|4|200605011006|21.6 22|5|4|200605011106|21.5 23|5|4|200605011206|21.2 27|3|2|200603020720|0.28 28|3|2|200603020820|0.65 29|3|2|200603020920|0.32 30|3|2|200603021020|0.28 31|3|2|200603021120|0.65 32|3|2|200603021220|0.32 33|3|2|200603021320|0.23 54|2|1|200605011206|18.9 55|2|1|200605011306|16.4 56|2|1|200605011406|15.3 57|2|1|200605011506|15.5 58|2|1|200605011606|15.8 59|2|1|200605011706|12.5 60|2|1|200605011806|13.6 61|2|1|200605011906|15.5 62|4|3|200605011206|0.3 63|4|3|200605011206|0.4 64|4|3|200605011206|0.2 65|4|3|200605011206|0.2 66|4|3|200605011206|0.3 67|4|3|200605011206|0.3 68|4|3|200605011206|0.2 69|4|3|200605011206|0.4 95|6|6|200603022320|14.23 96|6|6|200603022420|16.23 97|6|6|200603022020|23.23 98|6|6|200603022120|21.23 99|6|6|200603022220|23.23 100|6|6|200603022320|22.23 101|6|6|200603022420|22.23 另外这里用到zieckey.db
数据库内容： BEGIN TRANSACTION; CREATE TABLE SensorData( ID INTEGER PRIMARY KEY,SensorID INTEGER,SiteNum INTEGER,Time VARCHAR(12),SensorParameter REAL ); INSERT INTO "SensorData" VALUES(1,1,'200605011206',18.9); INSERT INTO "SensorData" VALUES(2,'200605011306',16.4); INSERT INTO "SensorData" VALUES(3,'200605011406',15.3); INSERT INTO "SensorData" VALUES(4,'200605011506',15.5); INSERT INTO "SensorData" VALUES(5,'200605011606',15.8); INSERT INTO "SensorData" VALUES(6,'200605011706',12.5); INSERT INTO "SensorData" VALUES(7,'200605011806',5.8); INSERT INTO "SensorData" VALUES(8,8,5,7); INSERT INTO "SensorData" VALUES(9,6); INSERT INTO "SensorData" VALUES(10,5); INSERT INTO "SensorData" VALUES(11,6); INSERT INTO "SensorData" VALUES(12,5); INSERT INTO "SensorData" VALUES(13,6); INSERT INTO "SensorData" VALUES(14,7); INSERT INTO "SensorData" VALUES(17,4,'200605010606',21.6); INSERT INTO "SensorData" VALUES(18,'200605010706',21.5); INSERT INTO "SensorData" VALUES(19,'200605010806',21.2); INSERT INTO "SensorData" VALUES(20,'200605010906',21.3); INSERT INTO "SensorData" VALUES(21,'200605011006',21.6); INSERT INTO "SensorData" VALUES(22,'200605011106',21.5); INSERT INTO "SensorData" VALUES(23,21.2); INSERT INTO "SensorData" VALUES(27,3,2,'200603020720',0.28); INSERT INTO "SensorData" VALUES(28,'200603020820',0.65); INSERT INTO "SensorData" VALUES(29,'200603020920',0.32); INSERT INTO "SensorData" VALUES(30,'200603021020',0.28); INSERT INTO "SensorData" VALUES(31,'200603021120',0.65); INSERT INTO "SensorData" VALUES(32,'200603021220',0.32); INSERT INTO "SensorData" VALUES(33,'200603021320',0.23); INSERT INTO "SensorData" VALUES(54,18.9); INSERT INTO "SensorData" VALUES(55,16.4); INSERT INTO "SensorData" VALUES(56,15.3); INSERT INTO "SensorData" VALUES(57,15.5); INSERT INTO "SensorData" VALUES(58,15.8); INSERT INTO "SensorData" VALUES(59,12.5); INSERT INTO "SensorData" VALUES(60,13.6); INSERT INTO "SensorData" VALUES(61,'200605011906',15.5); INSERT INTO "SensorData" VALUES(62,0.3); INSERT INTO "SensorData" VALUES(63,0.4); INSERT INTO "SensorData" VALUES(64,0.2); INSERT INTO "SensorData" VALUES(65,0.2); INSERT INTO "SensorData" VALUES(66,0.3); INSERT INTO "SensorData" VALUES(67,0.3); INSERT INTO "SensorData" VALUES(68,0.2); INSERT INTO "SensorData" VALUES(69,0.4); INSERT INTO "SensorData" VALUES(95,6,'200603022320',14.23); INSERT INTO "SensorData" VALUES(96,'200603022420',16.23); INSERT INTO "SensorData" VALUES(97,'200603022020',23.23); INSERT INTO "SensorData" VALUES(98,'200603022120',21.23); INSERT INTO "SensorData" VALUES(99,'200603022220',23.23); INSERT INTO "SensorData" VALUES(100,22.23); INSERT INTO "SensorData" VALUES(101,22.23); COMMIT; 另外感谢武汉大学 zHaocHen 朋友所给的帮助。
原文链接：https://www.f2er.com/sqlite/203258.html
