sqlite学习笔记10：C语言中使用sqlite之查询和更新数据

前面说到的 sqlite_exec() 中的第三个参数， SQLite 将为 sql 参数内执行的每个 SELECT 语句中处理的每个记录调用这个回调函数。

本节添加了两个函数，selectFromTable和updateTable.

实例程序如下：

#include 
#include 
#include "sqlite/sqlite3.h"

#define DB_NANE "sqlite/test.db"

sqlite3 *db = NULL;
char* sql = NULL;
char *zErrMsg = NULL;
const char* data = "Callback function called";/* 改为全局的 */
int ret = 0;

typedef enum{
    false,
    true
} bool;

/*
typedef int (*sqlite3_callback)(
void*,    Data provided in the 4th argument of sqlite3_exec()
int,      The number of columns in row
char**,   An array of strings representing fields in the row
char**    An array of strings representing column names
);
*/
static int callback(void *NotUsed, int argc, char **argv, char **azColName)
{
    int i = 0;
    for(i=0; i 
bool selectFromTable()/*新加*/
{
    /* Create SQL statement */
    sql = "SELECT * from COMPANY";
    
    /* Execute SQL statement */
    ret = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
    if( ret != SQLITE_OK ){
        fprintf(stderr, "Error SQL: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
        return false;
    }
    
    fprintf(stdout, "successfully operation done\n");
    
    return true;
}

bool updateTable()/* 新加 */
{
&＃160; &＃160; /* Create merged SQL statement */
&＃160; &＃160; sql = "UPDATE COMPANY set SALARY = 25000.00 where ID=1; " \
&＃160; &＃160; "SELECT * from COMPANY";
&＃160; &＃160;&＃160;
&＃160; &＃160; /* Execute SQL statement */
&＃160; &＃160; ret = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
&＃160; &＃160; if( ret != SQLITE_OK ){
&＃160; &＃160; &＃160; &＃160; fprintf(stderr, "SQL error: %s\n", zErrMsg);
&＃160; &＃160; &＃160; &＃160; sqlite3_free(zErrMsg);
&＃160; &＃160; &＃160; &＃160;&＃160;
&＃160; &＃160; &＃160; &＃160; return false;
&＃160; &＃160; }
&＃160; &＃160;&＃160;
&＃160; &＃160; fprintf(stdout, "Successfully operation done \n");
&＃160; &＃160;&＃160;
&＃160; &＃160; return true;
}







bool closeDB()
{
    int ret = 0;
    ret = sqlite3_close(db);
    if ( ret == SQLITE_BUSY ){
        return false;
    }
    
    return true;
}

int main(int argc, char* argv[])
{
    connectDB();
    /*createTable();*/
    /*insertRecords();*/
    selectFromTable();
    updateTable();
    selectFromTable();
    closeDB();
    
    return 0;
}