SQLITE的C语言接口

从网上找到了一个开源免费的数据库开发工具--sqlite,网上的关于sqlite的介绍有很多，详细见官方网站:http://www.sqlite.com.cn/ . 我发现sqlite正是我需要的. 总结一下几个特点:
1. 开放源代码
2. 程序特别小，在windows下应用程序sqlite.exe仅仅200kb以内。
3. 支持大多数sql指令，速度极快
4. 直接创建一个xxx.db,就是一个数据库，不需要服务器支持
5. 简洁的C语言API接口

基于上面几点,足可以看出sqlite的强大和优异之处。源代码公开和程序特别小，甚至可以跨平台直接编译"gcc -o sqlite3 *",将这融合到潜入式系统是多么的美妙！

在ubuntu6.10平台安装sqlite3及其开发包:
#sudo apt-get install sqlite3 libsqlite3-dev

链接这篇文章介绍了sqlite的使用方法:
http://www.sqlite.com.cn/MySqlite/4/378.Html

下面是我总结的sqlite3与C接口的API
我用到的主要是下面几个函数(头文件sqlite3.h):
int sqlite3_open(const char*,sqlite3**); //打开一个数据库
int sqlite3_close(sqlite3*); //关闭
int sqlite3_exec(sqlite3*,const char *sql,sqlite_callback,void*,char**);//执行
int sqlite3_get_table(sqlite3*,char***result,int *nrow,int *ncolumn,char **errmsg );
//result中是以数组的形式存放所查询的数据，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，没有查到结果时返回0
sqlite3_errcode() 通常用来获取最近调用的API接口返回的错误代码.
sqlite3_errmsg() 则用来得到这些错误代码所对应的文字说明.

exec错误码
#define SQLITE_OK 0 /* Successful result */
#define SQLITE_ERROR 1 /* SQL error or missing database */
#define SQLITE_INTERNAL 2 /* An internal logic error in SQLite */
#define SQLITE_PERM 3 /* Access permission denied */
#define SQLITE_ABORT 4 /* Callback routine requested an abort */
#define SQLITE_BUSY 5 /* The database file is locked */
#define SQLITE_LOCKED 6 /* A table in the database is locked */
#define SQLITE_NOMEM 7 /* A malloc() failed */
#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite_interrupt() */
#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
#define SQLITE_NOTFOUND 12 /* (Internal Only) Table or record not found */
#define SQLITE_FULL 13 /* Insertion failed because database is full */
#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
#define SQLITE_EMPTY 16 /* (Internal Only) Database table is empty */
#define SQLITE_SCHEMA 17 /* The database schema changed */
#define SQLITE_TOOBIG 18 /* Too much data for one row of a table */
#define SQLITE_CONSTRAINT 19 /* Abort due to contraint violation */
#define SQLITE_MISMATCH 20 /* Data type mismatch */
#define SQLITE_MISUSE 21 /* Library used incorrectly */
#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
#define SQLITE_AUTH 23 /* Authorization denied */
#define SQLITE_ROW 100 /* sqlite_step() has another row ready */
#define SQLITE_DONE 101 /* sqlite_step() has finished executing */
应用实例：

定义
sqlite3 *db = NULL;
char * errMsg = NULL;
char sql_cmd[200];

打开文件:
int rc = sqlite3_open("xxx.db",&db);
if(rc) //打开失败
printf("Open database failed!n");
else
printf("create the database successful!n");

建立表格:
sprintf(sql_cmd,"CREATE TABLE datapro(package INTEGER,offset
INTEGER,lklen INTEGER,base INTEHER,link INTEGER,err INTEGER);");
rc=sqlite3_exec(db,sql_cmd,&eMsg); //建立表datapro
if(rc==SQLITE_OK) //建表成功
printf("create the chn_to_eng table successful!n");
else
printf("%sn",eMsg);
添加数据:
sprintf(sql_cmd,"INSERT INTO datapro VALUES(%d,%d,%d);",4,2345,268,9,3,3);
rc=sqlite3_exec(pro_db,pro_sqlcmd,&eMsg);

查询:
int nrow=0,ncolumn=0;
char **azResult; //存放结果
sql="SELECT * FROM datapro";
sqlite3_get_table(db,sql,&azResult,&nrow,&ncolumn,&eMsg);
//其中nrow为行数，ncolum为列数
printf("nThe result of querying is : n");
for(int i=1;i<nrow+1;i++)
{
for(int j=0;j<ncolumn;j++)
printf("%s ",azResult[i*ncolumn+j]);
printf("n");
}

删除: sprintf(sql_cmd,"DELETE FROM datapro WHERE package=1;") ; rc=sqlite3_exec(db,&eMsg);

（编辑：李大同）

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