1、sqlite（了解即可）-FMDB（必须掌握2个小方法）

第三方库 github上的 FMDB   依赖于sqlite3动态库  libsqlite3.dylib

必须掌握的2个小方法

代码：

//
//  HMViewController.m

#import "HMViewController.h"
//#import "FMDB.h"
#import "HMShop.h"
#import "HMShopTool.h"

@interface HMViewController ()
//@property (nonatomic, strong) FMDatabase *db;
@end

@implementation HMViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    // 1.打开数据库
//    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"shops.sqlite"];
//    self.db = [FMDatabase databaseWithPath:path];
//    [self.db open];
//    
//    // 2.创表
//    [self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_shop (id integer PRIMARY KEY, name text NOT NULL, price real);"];
    // executeQuery:查询数据
//    [self.db executeQuery:<#(NSString *), ...#>];
    
    // executeUpdate:除查询数据以外的其他操作
//    [self.db executeUpdate:<#(NSString *), ...#>];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//    for (int i = 0; i<100; i++) {
//        HMShop *shop = [[HMShop alloc] init];
//        shop.name = [NSString stringWithFormat:@"枕头--%d", i];
//        shop.price = arc4random() % 200;
//        [HMShopTool addShop:shop];
//    }
    
    NSArray *shops = [HMShopTool shops];
    for (HMShop *shop in shops) {
        NSLog(@"%@ %f", shop.name, shop.price);
    }
    
//    [self.db executeUpdate:@"DELETE FROM t_shop WHERE price < 800;"];
//    
//    [self query];
}

- (void)query
{
    // 得到结果集
//    FMResultSet *set = [self.db executeQuery:@"SELECT * FROM t_shop;"];
//    
//    // 不断往下取数据
//    while (set.next) {
//        // 获得当前所指向的数据
//        NSString *name = [set stringForColumn:@"name"];
//        double price = [set doubleForColumn:@"price"];
//        NSLog(@"%@ %f", name, price);
//    }
}

- (void)insert
{
//    for (int i = 0; i<100; i++) {
//        NSString *name = [NSString stringWithFormat:@"手机-%d", i];
//#warning 这里的字符串不用再加上''
//        [self.db executeUpdateWithFormat:@"INSERT INTO t_shop(name, price) VALUES (%@, %d);", name, arc4random()%1000];
//    }
}

@end

 

//
//  HMShopTool.h

#import <Foundation/Foundation.h>
@class HMShop;

@interface HMShopTool : NSObject
+ (NSArray *)shops;
+ (void)addShop:(HMShop *)shop;
@end

 

//
//  HMShopTool.m

#import "HMShopTool.h"
#import "FMDB.h"
#import "HMShop.h"

@implementation HMShopTool

static FMDatabase *_db;

+ (void)initialize
{
    // 1.打开数据库
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"shops.sqlite"];
    _db = [FMDatabase databaseWithPath:path];
    [_db open];
    
    // 2.创表
    [_db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_shop (id integer PRIMARY KEY, name text NOT NULL, price real);"];
}

+ (void)addShop:(HMShop *)shop
{
    [_db executeUpdateWithFormat:@"INSERT INTO t_shop(name, price) VALUES (%@, %f);", shop.name, shop.price];
}

+ (NSArray *)shops
{// 得到结果集
    FMResultSet *set = [_db executeQuery:@"SELECT * FROM t_shop;"];
    
    // 不断往下取数据
    NSMutableArray *shops = [NSMutableArray array];
    while (set.next) {
        // 获得当前所指向的数据
        HMShop *shop = [[HMShop alloc] init];
        shop.name = [set stringForColumn:@"name"];
        shop.price = [set doubleForColumn:@"price"];
        [shops addObject:shop];
    }
    return shops;
}
@end

 

 ------------------------------

sqlite 的SQL语句注意点：

-

-

 not null unique default   primary key约束

-

 联合主键 用不到 不需要了解

-

sqlite特殊点   primary key  === primary key auto_increment不需要写
primary key = not null unique auto_increment
-
 主键必须是interger类型

-

A表class_id添加外键为B表的id后   A.class_id的值必须只能设置为   B表的id取值数据

On Delete On Update级联用的很少 不需要掌握
student 表的class_id 引用class表的id表的   如果设置On Delete关系    那么删除   class表的某个id值
那么student.class_id = class.id 的都会被自动删除

 

 

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这里不用看 

sqlite3函数了解即可 纯c语言的东西   面试不会问

 

sqlite其他杂项:

 

plist preference只能设置基本数据
NSCoding可以设置对象
Sqlite3暂时了解即可   等会FMDB是必须掌握的

公司里常用的是Sqlite3      coreData即时通讯时候有