数据库 - FMDB

• FMDB是iOS平台的SQLite数据库框架

• FMDB以OC的方式封装了SQLite的C语言API

FMDB 需要libsqlite3.0 系统库的支持

/////////////////////////  实现代码   ////////////////////////////////////////////////

#import "PPFMDBTool.h"

#import "PPShop.h"

#import "FMDB.h"

@implementation PPFMDBTool

SingletonM(fmdbTool)

static FMDatabase *_db;

+ (void)initialize

{

    // 1. 打开数据库

    _db = [FMDatabase databaseWithPath:[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)  lastObject] stringByAppendingPathComponent:@"shop.sqilte"]];

    BOOL isSuc = [_db open];

    if (isSuc) {

        // 2. 创建表

        [_db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_shop (id integer PRIMARY KEY, name text NOT NULL, price real);"];

    }else{

        LogGreen(@"打开数据库 -- 失败");

    }

}

+ (void)insertShop:(PPShop *)shop

{

    [_db executeUpdateWithFormat:@"INSERT INTO t_shop(name, price) VALUES (%@, %f);", shop.name, shop.price];

}

+ (NSArray *)shops

{

    // 查询 - 得到结果集

    FMResultSet *set = [_db executeQuery:@"SELECT * FROM t_shop;"];

    NSMutableArray *shops = [NSMutableArray array];

    // 不断往下取数据

    while ([set next]) {

        // 获得当前所指向的数据

        PPShop *shop = [[PPShop alloc] init];

        shop.name = [set stringForColumn:@"name"];

        shop.price = [set doubleForColumn:@"price"];

        [shops addObject:shop];

    }

    return shops;

}

+ (void)deleteShop{

    // 删除 价格低于500 的记录

    [_db executeUpdate:@"DELETE FROM t_shop WHERE price < 5000;"];

}