数据库工具类 (通过外面传入一个数值和表中字段值进行比较)
#import
@interface QJFMDBTool : NSObject
/**
* 根据外面传入一个数值和表中字段值进行比较
*
* @param params 比较的参数
*/
+ (NSArray *)compareWithParams:(NSString *)str;
/**
* 存储数据到沙盒中
*
* @param goods 需要存储的数据
*/
+ (void)saveGoods:(NSArray *)goods;
+ (NSArray *)delGoods:(NSString *)str;
@end
#import "QJFMDBTool.h"
#import "FMDB.h"
@implementation QJFMDBTool
static FMDatabase *_db;
+ (void)initialize
{
// 1.打开数据库
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"goods.sqlite"];
_db = [FMDatabase databaseWithPath:path];
[_db open];
// 2.创表
[_db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_goods (goodIdtext PRIMARY KEY, good blob NOT NULL);"];
}
+ (NSArray *)compareWithParams:(NSString *)str
{
// SELECT 列名称 FROM 表名称 WHERE列 运算符 值
NSString *sql = [NSStringstringWithFormat:@"SELECT * FROM t_goods WHERE goodId = %@ ;", str];
// 执行SQL
FMResultSet *set = [_db executeQuery:sql];
NSMutableArray *datas = [NSMutableArray array];
while (set.next) {
NSData *goodsData = [set objectForColumnName:@"good"];
NSDictionary *goodD = [NSKeyedUnarchiver unarchiveObjectWithData:goodsData];
[datas addObject:goodD];
}
return datas;
}
+ (void)saveGoods:(NSArray *)goods
{
// 要将一个对象存进数据库的blob字段,最好先转为NSData
// 一个对象要遵守NSCoding协议,实现协议中相应的方法,才能转成NSData
for (NSDictionary *good in goods) {
// NSDictionary --> NSData
NSData *goodsData = [NSKeyedArchiver archivedDataWithRootObject:good];
[_db executeUpdateWithFormat:@"INSERT INTO t_goods(goodId, good) VALUES (%@, %@);", good[@"goodId"],goodsData];
}
}
+ (NSArray *)delGoods:(NSString *)str
{
// DELETE FROM 表名称 WHERE 列名称 = 值
NSString *sql = [NSString stringWithFormat:@"DELETE FROM t_goods WHERE goodId = %@ ;", str];
// 执行SQL
FMResultSet *set = [_db executeQuery:sql];
NSMutableArray *datas = [NSMutableArray array];
while (set.next) {
NSData *goodsData = [set objectForColumnName:@"good"];
NSDictionary *goodD = [NSKeyedUnarchiver unarchiveObjectWithData:goodsData];
[datas addObject:goodD];
}
return datas;
}