fmdb是基于sqlite3基础上进行封装,概念性的东西不多说,本demo采用的是队列方式,可以保证线程安全
demo演示
//主要代码:事务回滚,有兴趣的朋友可以自行添加
@implementation DBObject
+(instancetype)sharedInstance{
static DBObject *sql = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sql = [[DBObject alloc]init];
});
return sql;
}
/**
* 初始化字典
*
* @return <#return value description#>
*/
-(NSMutableDictionary *)params{
if (!_params) {
_params = [NSMutableDictionary dictionary];
}
return _params;
}
/**
* 初始化数组(查找全部)
*
* @return <#return value description#>
*/
-(NSMutableArray *)Array{
if (!_Array) {
_Array = [NSMutableArray array];
}
return _Array;
}
/**
* 新建数据库+新建表
*/
-(void)addDatabaseAndTableMethod{
NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)firstObject];
//拼接文件名
NSString *filePath = [cachePath stringByAppendingString:@"note.sqlite"];
NSLog(@"数据库路径:%@",filePath);
//创建数据库,并加入到队列中,此时已经默认打开了数据库,无须手动打开,只需要从队列中去除数据库即可
self.queue = [FMDatabaseQueue databaseQueueWithPath:filePath];
//取出数据库,这里的db就是数据库,在数据库中建表
[self.queue inDatabase:^(FMDatabase *db) {
BOOL createTable = [db executeUpdate:@"create table if not exists t_note (id integer primary key autoincrement,title text,name text,password text)"];
if (createTable) {
NSLog(@"创建表成功");
}
else{
NSLog(@"创建表失败");
}
}];
}
/**
* 新增
*/
-(void)insetTitle:(NSString *)title WithName:(NSString *)name WithPassWord:(NSString *)password{
[self.queue inDatabase:^(FMDatabase *db) {
BOOL flag = [db executeUpdate:@"insert into t_note (title,name,password) values (?,?,?)",title,name,password];
if (flag) {
NSLog(@"新增数据成功");
}
else{
NSLog(@"新增数据失败");
}
}];
}
/**
* 删除
*/
-(void)deleteWithTitle:(NSString *)title{
[self.queue inDatabase:^(FMDatabase *db) {
BOOL flag = [db executeUpdate:@"delete from t_note where title = ?",title];
if (flag) {
NSLog(@"删除数据成功");
}
else{
NSLog(@"删除数据失败");
}
}];
}
/**
* 更新数据
*/
-(void)updateWithNewName:(NSString *)newName WithTitle:(NSString *)title{
[self.queue inDatabase:^(FMDatabase *db) {
BOOL flag = [db executeUpdate:@"update t_note set name = ? where title = ?",newName,title];
if (flag) {
NSLog(@"更新数据成功");
}
else{
NSLog(@"更新数据失败");
}
}];
}
/**
* 条件查询数据
*/
-(void)selectWithTitle:(NSString *)title{
[self.queue inDatabase:^(FMDatabase *db) {
//获取结果集,返回参数就是查询结果
FMResultSet *rs = [db executeQuery:@"select *from t_note where title = ?",title];
while ([rs next]) {
self.title = [rs stringForColumn:@"title"];
self.name = [rs stringForColumn:@"name"];
self.password = [rs stringForColumn:@"password"];
NSLog(@"平台:%@---用户名:%@----密码:%@",self.title,self.name,self.password);
//先将数据存放到字典
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
[dic setObject:self.title forKey:@"dictTitle"];
[dic setObject:self.name forKey:@"dictName"];
[dic setObject:self.password forKey:@"dictPwd"];
//然后将字典存放到数组
[self.Array addObject:dic];
}
}];
}
/**
* 查询所有数据
*
*/
-(void)selectAllMethod{
//每次进来查询的时候,先清除上次缓存数据
[self.Array removeAllObjects];
[self.queue inDatabase:^(FMDatabase *db) {
//获取结果集,返回参数就是查询结果
FMResultSet *rs = [db executeQuery:@"select *from t_note"];
while ([rs next]) {
self.title = [rs stringForColumn:@"title"];
self.name = [rs stringForColumn:@"name"];
self.password = [rs stringForColumn:@"password"];
NSLog(@"平台:%@---用户名:%@----密码:%@",self.title,self.name,self.password);
//先将数据存放到字典
NSMutableDictionary *dic = [NSMutableDictionary dictionary];
[dic setObject:self.title forKey:@"dictTitle"];
[dic setObject:self.name forKey:@"dictName"];
[dic setObject:self.password forKey:@"dictPwd"];
//然后将字典存放到数组
[self.Array addObject:dic];
}
NSLog(@"存放的数组:%@==%ld",self.Array,self.Array.count);
[[NSUserDefaults standardUserDefaults]setObject:self.Array forKey:@"Arry"];
[[NSUserDefaults standardUserDefaults]synchronize];
}];
}
/**
* 事务回滚写法1: (如果要保证多个操作同时成功或者同时失败，用事务，即把多个操作放在同一个事务中。)
*/
-(void)updateFailure:(id)sender{
[self.queue inDatabase:^(FMDatabase *db) {
[db beginTransaction];
[db executeUpdate:@"update t_note set name = 'jack' where password = ?",@"12"];
[db executeUpdate:@"update t_note set name = 'tony' where password = ?",@"13"];
//发现情况不对,主动回滚用下面语句.否则是根据commit结果,如成功就成功，如不成功才回滚
[db rollback];
[db executeUpdate:@"update t_note set name = '回滚' where password = ?",@"13"];
[db commit];
}];
}
/**
* 事务回滚写法2:(直接利用队列进行事务操作,队列中的打开、关闭、回滚事务等都已经被封装好了)
*/
-(void)updateFailure02:(id)sender{
[self.queue inDatabase:^(FMDatabase *db) {
[self.queue inTransaction:^(FMDatabase *db, BOOL *rollback) {
[db executeUpdate:@"update t_note set name = 'jack' where password = ?",@"12"];
[db executeUpdate:@"update t_note set name = 'tony' where password = ?",@"13"];
//发现情况不对,主动回滚用下面语句
*rollback = YES;
[db executeUpdate:@"update t_note set name = '回滚' where password = ?",@"13"];
}];
}];
}
/**
* 回滚的原生代码:
[db executeUpdate:@"BEGIN TRANSACTION"];
[db executeUpdate:@"ROLLBACK TRANSACTION"];
[db executeUpdate:@"COMMIT TRANSACTION"];
*/
demo链接:https://github.com/OwenJoe/FMDB.git
iOS开发之FMDB图片的增删查改,请参阅:
链接:http://www.jianshu.com/p/6edcfe58aaf0
