C语言封装sqlite3_API

//执行类似insert,update,create,drop这些不需要结果的sql语句。

int executeNoQuery(sqlite3 *db,const char *sql)
 {
    sqlite3_stmt *pstmt = NULL;
 
     if(sqlite3_prepare_v2(db,sql,strlen(sql),&pstmt,NULL)  !=  SQLITE_OK)
     {
         if(pstmt != NULL)
             sqlite3_finalize(pstmt);
        fprintf(stderr,"%s\n",sqlite3_errmsg(db));
         return -1;
     }
     if(sqlite3_step(pstmt)  !=  SQLITE_DONE)
     {
         sqlite3_finalize(pstmt);
         fprintf(stderr,"%s\n",sqlite3_errmsg(db));
         return -1;
    }
     if(pstmt != NULL)
         sqlite3_finalize(pstmt);
     return 0;
 }

//执行select查询语句

void executeWithQuery(sqlite3 *db,char ***result,int *col,const char *sql)
  {
      int ret,row;
      char *errMsg;
  
      ret = sqlite3_get_table(db,sql,result,&row,col,&errMsg);
      if(ret != SQLITE_OK)
      {
          fprintf(stderr,"%s\n",errMsg);
          sqlite3_free(errMsg);
          return;
      }
      (*result)[(row+1)*(*col)] = NULL;
      return;
  }

调用规则：

executeNoQuery：

只需传入数据库连接，和想要执行的sql语句

executeWithQuery：除了需要传入数据库连接，以及最后一个参数sql语句，还需要传入char **array,和int ncol的地址

下面是一个例子：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sqlite3.h>

#define PRINTERROR(str)	\
	do{	\
		perror(str);\
		exit(EXIT_FAILURE);	\
	}while(0)

const char *createSQL = "create table if not exists T_Students\
(S_id integer PRIMARY KEY NOT NULL,\
S_name varchar(128),S_age integer,\
Time TimeStamp NOT NULL DEFAULT (datetime('now','localtime')));";

const char *deleteSQL = "delete from T_Students where S_name='sagarfan';";
const char *updateSQL = "update T_Students set S_age=25 where S_name='sagarfan';";
const char *insertSQL = "insert into T_Students (S_name,S_age) values('sagarfan',23);";
const char *selectSQL = "select S_name,S_age from T_Students;";

int executeNoQuery(sqlite3 *db,const char *sql);
int executeWithQuery(sqlite3 *db,char ***result,int *col,const char *sql);

int main()
{
	sqlite3 *conn = NULL;
	int i,ret,ncol;char sql[1024]={0}; 
	char **array;

	ret = sqlite3_open("stu.sqlite",&conn);
	if(ret != SQLITE_OK)
		PRINTERROR(sqlite3_errmsg(conn));
	//create table
	ret = executeNoQuery(conn,createSQL);
	if(ret == -1)
		PRINTERROR(sqlite3_errmsg(conn));

	ret = executeNoQuery(conn,insertSQL);
	if(ret == -1)
		PRINTERROR(sqlite3_errmsg(conn));

	ret = executeWithQuery(conn,&array,&ncol,selectSQL);
	if(ret == -1)
		PRINTERROR(sqlite3_errmsg(conn));
	i=0;
	while(array[i+ncol] != NULL)
	{
		printf("Name=%s\n",array[i+ncol]);
		printf("Age=%s\n",array[i+1+ncol]);
		i+=ncol;
	}
	sqlite3_free_table(array);

	ret = executeNoQuery(conn,updateSQL);
	if(ret == -1)
		PRINTERROR(sqlite3_errmsg(conn));
	
	if(conn != NULL)
		sqlite3_close(conn);

	return 0;
}

int executeNoQuery(sqlite3 *db,const char *sql)
{
	sqlite3_stmt *pstmt = NULL;

	if(sqlite3_prepare_v2(db,sql,strlen(sql),&pstmt,NULL) != SQLITE_OK)
	{
		if(pstmt != NULL)
			sqlite3_finalize(pstmt);
		return -1;
	}
	if(sqlite3_step(pstmt) != SQLITE_DONE)
	{
		sqlite3_finalize(pstmt);
		return -1;
	}
	sqlite3_finalize(pstmt);
	return 0;
}

int executeWithQuery(sqlite3 *db,char ***result,int *col,const char *sql)
{
	int ret,row;

	ret = sqlite3_get_table(db,sql,result,&row,col,NULL);
	if(ret != SQLITE_OK)
	{
		return -1;
  	}
 	(*result)[(row+1)*(*col)] = NULL;

	return 0;
}

注意：

调用完executeWithQuery之后，记得释放array