前面说到的 sqlite_exec() 中的第三个參数， SQLite 将为 sql 參数内运行的每一个 SELECT 语句中处理的每一个记录调用这个回调函数。

本节加入了两个函数。selectFromTable和updateTable.

实例程序例如以下：

#include <stdio.h>

#include <stdlib.h>

#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 < argc; i++){

        printf("%s = %s\n", azColName[i], argv[i] ?

argv[i] : "NULL");

    }

    printf("\n");

    return 0;

}

bool connectDB()

{

    ret = sqlite3_open(DB_NANE, &db);

    if( ret != SQLITE_OK){

        fprintf(stderr, "Error open database: %s\n", sqlite3_errmsg(db));

        sqlite3_free(zErrMsg);

        return false;

    }

    fprintf(stdout, "Successfully opened database\n");

    return true;

}

bool createTable()

{

    /* Create SQL statement */

    sql = "CREATE TABLE COMPANY("  \

    "ID INT PRIMARY KEY     NOT NULL," \

    "NAME           TEXT    NOT NULL," \

    "AGE            INT     NOT NULL," \

    "ADDRESS        CHAR(50)," \

    "SALARY         REAL );";

    /* Execute SQL statement */

    ret = sqlite3_exec(db, sql, callback, 0, &zErrMsg);

    if( ret != SQLITE_OK ){

        fprintf(stderr, "Error SQL: %s\n", zErrMsg);

        sqlite3_free(zErrMsg);

        return false;

    }

    fprintf(stdout, "Successfully table created\n");

    return true;

}

bool insertRecords()

{

    /* Create SQL statement */

    sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) "  \

    "VALUES (1, 'Paul', 32, 'California', 20000.00 ); " \

    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) "  \

    "VALUES (2, 'Allen', 25, 'Texas', 15000.00 ); "     \

    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" \

    "VALUES (3, 'Teddy', 23, 'Norway', 20000.00 );" \

    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" \

    "VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 );";

    /* Execute SQL statement */

    ret = sqlite3_exec(db, sql, callback, 0, &zErrMsg);

    if( ret != SQLITE_OK ){

        fprintf(stderr, "SQL error: %s\n", zErrMsg);

        sqlite3_free(zErrMsg);

        return false;

    }

    fprintf(stdout, "successfully records created\n");

    return true;

}

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 */

{

    /* Create merged SQL statement */

    sql = "UPDATE COMPANY set SALARY = 25000.00 where ID=1; " \

    "SELECT * from COMPANY";

    

    /* Execute SQL statement */

    ret = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);

    if( ret != SQLITE_OK ){

        fprintf(stderr, "SQL error: %s\n", zErrMsg);

        sqlite3_free(zErrMsg);

        

        return false;

    }

    

    fprintf(stdout, "Successfully operation done \n");

    

    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;

}