封装数据库

#import "DBManager.h"
#import "FMDatabase.h"
@implementation DBManager
{
    FMDatabase *_fmdb;
    NSLock *_lock;
}
+(DBManager *)shareManager{
    static DBManager *manager=nil;
    static dispatch_once_t once;
    dispatch_once(&once, ^{
        if (manager==nil) {
            manager=[[DBManager alloc]init];
        }
    });
    return manager;
}

-(id)init{
    self=[super init];
    if (self) {
        
        _lock=[[NSLock alloc]init];
        
//        [_lock lock];  加锁
//        [_lock unlock];  解锁
        
        NSString *path=[NSHomeDirectory() stringByAppendingString:@"/Documents/user.db"];
        _fmdb=[[FMDatabase alloc]initWithPath:path];
        if ([_fmdb open]) {
            NSString *createSql=@"create table if not exists userInfo(id integer primary key autoincrement,name varchar(256),age integer,image blob)";//创建一个userInfo表，表中有id、name、age、image 四个属性。 blob 是用来存储2进制的。 integer 整型varchar(256) 字符型
            // create table if not exists 表名(属性 属性的类型，属性 属性的类型)
            //primary key 主键 autoincrement 自增
            BOOL success=[_fmdb executeUpdate:createSql];
            if (!success) {
                NSLog(@"create:%@",_fmdb.lastError);
            }
        }
    }
    return self;
}
// 插入数据
-(void)insertModel:(UserModel *)model{
    [_lock lock];
    NSString *insertSql=@"insert into userInfo(name,age,image) values(?,?,?)";
    //insert into 表名(属性名,属性名) values(?,?)
    UIImage *image=model.headImage;
    NSData *data=UIImagePNGRepresentation(image);//UIImagePNGRepresentation 这个方法是可以将png类型的图片转化成 NSData
    BOOL success=[_fmdb executeUpdate:insertSql,model.name,model.age,data];//executeUpdate 后面需要去接 继承与NSObject类所实例化的对象 否则会抛出EXC_BAD_ACCESS错误
    if (!success) {
        NSLog(@"%@",_fmdb.lastError);
    }
    [_lock unlock];
}
//删除数据
-(void)deleteDataWith:(NSNumber *)dataID{
    [_lock lock];
    NSString *deleteSql=@"delete from userInfo where id=?";// delete from 表名 where 属性＝?
    BOOL success=[_fmdb executeUpdate:deleteSql,dataID];
    if (!success) {
        NSLog(@"%@",_fmdb.lastError);
    }
    [_lock unlock];
}

-(void)updateWith:(UserModel *)model{
    [_lock lock];
    NSString *updateSql=@"update userInfo set name=?,age=?,image=? where id =?";// update 表名 set 属性名＝？,属性名＝？ where 属性名＝？
    UIImage *image=model.headImage;
    NSData *data=UIImagePNGRepresentation(image);
    NSNumber *IDNum=[NSNumber numberWithInteger:[model.id1 integerValue]];
    BOOL success=[_fmdb executeUpdate:updateSql,model.name,model.age,data,IDNum];
    if (!success) {
        NSLog(@"%@",_fmdb.lastError);
    }
    [_lock unlock];
}

-(NSArray *)selectAllData{
    [_lock lock];
    NSString *selSQL=@"select * from userInfo";//* 查找全部 select * from 表名
    FMResultSet *set=[_fmdb executeQuery:selSQL];
    NSMutableArray *array=[[NSMutableArray alloc]init];
    while ([set next]) {
        UserModel *model=[[UserModel alloc]init];
        model.name=[set stringForColumn:@"name"];
        NSData *data=[set dataForColumn:@"image"];
        UIImage *image=[UIImage imageWithData:data];//把NSData类型的数据转化成image
        model.headImage=image;
        model.age=[NSNumber numberWithInteger:[[set stringForColumn:@"age"] integerValue]];
        [array addObject:model];
    }
    [_lock unlock];
    return [array copy];
}
// 查找一条语句是否存在
-(BOOL)isOrNotIN:(NSNumber *)idOne{
    NSString *sql=@"select * from userInfo where id=?";//
    FMResultSet *set=[_fmdb executeQuery:sql];
    return [set next];
}


@end