IOS sqlite3 数据增删改查

//
// CLViewController.m
// LessonDatabase
//
// Created by lanouhn on 14-9-19.
// Copyright (c) 2014年 [email protected] 陈聪雷. All rights reserved.
//

#import "CLViewController.h"
#import "DatabaseHelper.h"
#import "Student.h"
@interface CLViewController ()

@end

@implementation CLViewController

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//数据库(Database): 存放数据的仓库, 存放的是一张的表, 特别像Excel, Numbers, 都以表格的形式存放数据, 可以创建多张表
//常见的数据库: sqlite, MySQL, SQLServer, Oracle, Access
//为什么要用数据库 1 文件读写和归档读取数据需要一次把数据全部读出来, 占用内存开销大 2 数据库数据效率高, 体现在增删改查
//SQL Structured Query Language 用于对数据库的操作语句 (增删改查)
//SQL 语句不区分大小写, 字符串需要加""或''
//主键: 是一条数据的唯一标示符, 一张表只能有一个主键, 主键不能够重复, 一般把主键名设为"id", 不需要赋值, 会自增
//*代表所有的字段
//where是条件
//创建表: creat table 表名 (字段名字段数据类型是否为主键, 字段名字段数据类型, 字段名字段数据类型...)
//查: select 字段名 (或者*) from 表名 where 字段名 = 值
//增: insert into 表名 (字段1, 字段2...) values (值1, 值2...)
//改: update 表名 set 字段 = 值 where 字段 = 值
//删: delete from 表名 where 字段 = 值

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

- (IBAction)selectAll:(id)sender {
NSMutableArray *array = [DatabaseHelper getAllStudents];
for (Student *stu in array) {
NSLog(@"%@", stu);
}
}

- (IBAction)selectOne:(id)sender {
Student *stu = [DatabaseHelper getStudentWithID:2];
NSLog(@"%@", stu);
}

- (IBAction)insetOne:(id)sender {
Student *stu = [[Student alloc] init];
stu.name = @"vaercly";
stu.sex = @"man";
stu.age = 22;
BOOL result = [DatabaseHelper insertStudent:stu];
NSLog(@"%d", result);
}

- (IBAction)updateName:(id)sender {
[DatabaseHelper updateStudentName:@"陈聪雷" byID:5];
}

- (IBAction)deleteOne:(id)sender {
[DatabaseHelper deleteStudentWithID:5];
}
@end
//
// Datebase.m
// LessonDatabase
//
// Created by lanouhn on 14-9-19.
// Copyright (c) 2014年 [email protected] 陈聪雷. All rights reserved.
//
#define FILE_NAME @"Database.sqlite"
#import "Database.h"
static sqlite3 *db = nil;
@implementation Database
//打开数据库
+ (sqlite3 *)openDB
{
if (!db) {
//1 获取document文件夹的路径
//参数1: 文件夹的名字参数2: 查找域参数3: 是否使用绝对路径
NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
//获取数据库文件的路径
NSString *dbPath = [docPath stringByAppendingPathComponent:FILE_NAME];
//iOS 中管理文件的类, 负责复制文件, 删除文件, 移动文件
NSFileManager *fm = [NSFileManager defaultManager];
//判断document中是否有sqlite文件
if (![fm fileExistsAtPath:dbPath]) {
//获取在*.app中sqlite文件的路径
NSString *boundlePath = [[NSBundle mainBundle] pathForResource:@"Database" ofType:@"sqlite"];
NSError *error = nil;
//将*.app中sqlite文件复制一份到dbPath
BOOL result = [fm copyItemAtPath:boundlePath toPath:dbPath error:&error];
//若复制文件失败, 打印错误信息
if (!result) {
NSLog(@"%@", error);
}
}
//打开数据库参数1: 文件路径(UTF8String可以将OC的NSString转为C中的char) 参数2: 接受数据库的指针
sqlite3_open([dbPath UTF8String], &db);
}
return db;
}

//关闭数据库
+ (void)closeDB
{
sqlite3_close(db);
db = nil;
}
@end
//
// DatabaseHelper.m
// LessonDatabase
//
// Created by lanouhn on 14-9-19.
// Copyright (c) 2014年 [email protected] 陈聪雷. All rights reserved.
//

#import "DatabaseHelper.h"
#import "Student.h"
#import "Database.h"
@implementation DatabaseHelper
//查询所有学生
+ (NSMutableArray *)getAllStudents
{
//打开数据库
sqlite3 *db = [Database openDB];
//数据库操作指针 stmt:statement
sqlite3_stmt *stmt = nil;
//验证SQL的正确性参数1: 数据库指针, 参数2: SQL语句, 参数3: SQL语句的长度 -1代表无限长(会自动匹配长度), 参数4: 返回数据库操作指针, 参数5: 为未来做准备的, 预留参数, 一般写成NULL
int result = sqlite3_prepare_v2(db, "select * from Student", -1, &stmt, NULL);
NSMutableArray *studentArr = [NSMutableArray array];
//判断SQL执行的结果
if (result == SQLITE_OK) {
while (sqlite3_step(stmt) == SQLITE_ROW) {//存在一行数据
//列数从0开始
int ID = sqlite3_column_int(stmt, 0);
const unsigned char *name = sqlite3_column_text(stmt, 1);
const unsigned char *sex = sqlite3_column_text(stmt, 2);
int age = sqlite3_column_int(stmt, 3);
//blob类型的获取
//1 获取长度
int length = sqlite3_column_bytes(stmt, 4);
//2 获取数据
const void *photo = sqlite3_column_blob(stmt, 4);
//3 转成NSData
NSData *photoData = [NSData dataWithBytes:photo length:length];
//4 转成UIImage
UIImage *image = [UIImage imageWithData:photoData];
//封装Student模型
Student *student = [[Student alloc] init];
student.ID = ID;
student.name = [NSString stringWithUTF8String:(const char *)name];
student.sex = [NSString stringWithUTF8String:(const char *)sex];
student.age = age;
student.photo = image;
//添加到数组
[studentArr addObject:student];
}
}
//释放stmt指针
sqlite3_finalize(stmt);
//关闭数据库
[Database closeDB];
return studentArr;
}
//查询单个学生
+ (Student *)getStudentWithID:(NSInteger)aID
{
sqlite3 *db = [Database openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = [NSString stringWithFormat:@"select * from Student where id = %d", aID];
int result = sqlite3_prepare_v2(db, [sqlStr UTF8String], -1, &stmt, NULL);
Student *student = nil;
if (result == SQLITE_OK) {
if (sqlite3_step(stmt) == SQLITE_ROW) {
int ID = sqlite3_column_int(stmt, 0);
const unsigned char *name = sqlite3_column_text(stmt, 1);
const unsigned char *sex = sqlite3_column_text(stmt, 2);
int age = sqlite3_column_int(stmt, 3);
int length = sqlite3_column_bytes(stmt, 4);
const unsigned char *photo = sqlite3_column_blob(stmt, 4);
NSData *photoData = [NSData dataWithBytes:photo length:length];
UIImage *image = [UIImage imageWithData:photoData];
student = [[Student alloc] init];
student.ID = ID;
student.name = [NSString stringWithUTF8String:(const char *)name];
student.sex = [NSString stringWithUTF8String:(const char *)sex];
student.age = age;
student.photo = image;
}
}
sqlite3_finalize(stmt);
[Database closeDB];
return student;
}
//添加一个新学生
+ (BOOL)insertStudent:(Student *)aStudent
{
sqlite3 *db = [Database openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = [NSString stringWithFormat:@"insert into Student (name, sex, age) values ('%@', '%@', '%d')", aStudent.name, aStudent.sex, aStudent.age];
int result = sqlite3_prepare_v2(db, [sqlStr UTF8String], -1, &stmt, NULL);
if (result == SQLITE_OK) {
//判断语句执行完成没有
if (sqlite3_step(stmt) == SQLITE_DONE) {
sqlite3_finalize(stmt);
[Database closeDB];
return YES;
}
}
sqlite3_finalize(stmt);
[Database closeDB];
return NO;
}
//修改学生的姓名
+ (BOOL)updateStudentName:(NSString *)aName byID:(NSInteger)aID
{
sqlite3 *db = [Database openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = [NSString stringWithFormat:@"update Student set name = '%@' where id = %d", aName, aID];
int result = sqlite3_prepare_v2(db, [sqlStr UTF8String], -1, &stmt, NULL);
if (result == SQLITE_OK) {
if (sqlite3_step(stmt) == SQLITE_ROW) {//觉的应加一个判断, 若有这一行则修改
if (sqlite3_step(stmt) == SQLITE_DONE) {
sqlite3_finalize(stmt);
[Database closeDB];
return YES;
}
}
}
sqlite3_finalize(stmt);
[Database closeDB];
return NO;
}
//删除一个学生
+ (BOOL)deleteStudentWithID:(NSInteger)aID
{
sqlite3 *db = [Database openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = [NSString stringWithFormat:@"delete from Student where id = %d", aID];
int result = sqlite3_prepare_v2(db, [sqlStr UTF8String], -1, &stmt, NULL);
if (result == SQLITE_OK) {
if (sqlite3_step(stmt) == SQLITE_ROW) {//觉的应加一个判断, 若有这一行则删除
if (sqlite3_step(stmt) == SQLITE_DONE) {
sqlite3_finalize(stmt);
[Database closeDB];
return YES;
}
}
}
sqlite3_finalize(stmt);
[Database closeDB];
return NO;
}
@end
//
// Student.h
// LessonDatabase
//
// Created by lanouhn on 14-9-19.
// Copyright (c) 2014年 [email protected] 陈聪雷. All rights reserved.
//

#import <foundation foundation.h="">

@interface Student : NSObject
@property (nonatomic, assign) NSInteger ID;
@property (nonatomic, retain) NSString *name;
@property (nonatomic, retain) NSString *sex;
@property (nonatomic, assign) NSInteger age;
@property (nonatomic, retain) UIImage *photo;
@end
</foundation>

IOS sqlite3 数据增删改查

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