IOS 学习 数据库操作实例

// 0.定义数组
NSMutableArray *students = nil;

// 1.定义sql语句const char *sql = "select id, name, age from t_student;";// 2.定义一个stmt存放结果集sqlite3_stmt *stmt = NULL;// 3.检测SQL语句的合法性int result = sqlite3_prepare_v2(_db, sql, -1, &stmt, NULL);if (result == SQLITE_OK) {    NSLog(@"查询语句是合法的");    students = [NSMutableArray array];    // 4.执行SQL语句，从结果集中取出数据    while (sqlite3_step(stmt) == SQLITE_ROW) { // 真的查询到一行数据        // 获得这行对应的数据        IWStudent *student = [[IWStudent alloc] init];        // 获得第0列的id        student.ID = sqlite3_column_int(stmt, 0);        // 获得第1列的name        const unsigned char *sname = sqlite3_column_text(stmt, 1);        student.name = [NSString stringWithUTF8String:(const char *)sname];        // 获得第2列的age        student.age = sqlite3_column_int(stmt, 2);        // 添加到数组        [students addObject:student];    }} else {    NSLog(@"查询语句非合法");}return students;