fmdb 数据库的基本操作

/**

*  创建表

*/

- (void)createTable

{

//1.初始化数据库对象 并且 2.打开数据库

BOOL isOpenSuccess = [self.database open];

NSLog(@"数据库打开%@",isOpenSuccess?@"成功":@"失败");

//3.创建表

NSString *sql = @"create table if not exists User (id integer primary key autoincrement, name text, age integer, icon blob)";

//执行sql,除了查询外，其他的操作都是更新

BOOL isCreateTableOK = [self.database executeUpdate:sql];

NSLog(@"创建表%@",isCreateTableOK?@"成功":@"失败");

}

//初始化数据库对象

- (FMDatabase *)database

{

if (!_database)

{

_database = [FMDatabase databaseWithPath:[self databasePath]];

}

return _database;

}

/**

*  返回数据库路径

*

*  @return return value description

*/

- (NSString *)databasePath

{

//获取document路径

NSString *docuentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];

return [docuentPath stringByAppendingPathComponent:@"user.db"];

}

/**

*  插入指定数据

*

*  @param user user description

*

*  @return return value description

*/

- (BOOL)insertUserObjectWithUser:(User *)user

{

NSString *sql = @"insert into User (name,age,icon) values (?,?,?)";

//执行插入的sql语句

BOOL isInsertOK = [self.database executeUpdate:sql,user.name,@(user.age),user.iconData];

NSLog(@"插入数据%@",isInsertOK?@"成功":@"失败");

return YES;

}

/**

*  更新数据

*

*  @param user user description

*

*  @return return value description

*/

- (BOOL)updateUserObjectWithUser:(User *)user

{

NSString *sql = [NSString stringWithFormat:@"update user set name='%@',age='%d',icon='%@' where name = '%@'",user.name,user.age,user.iconData,user.name];

BOOL isInsertOK = [self.database executeUpdate:sql];

NSLog(@"==========更新数据%@===========",isInsertOK?@"成功":@"失败");

return YES;

}

/**

*  查询所有的数据

*

*  @return return value description

*/

- (NSArray *)queryAllUserObjectsFromDatabase

{

//保存所有的用户信息

NSMutableArray *users = [NSMutableArray array];

NSString *sql = @"select * from User";

//执行查询

FMResultSet *result = [self.database executeQuery:sql];

//遍历

while (result.next)

{

User *user = [[User alloc] init];

//取值

//根据字段名字取值

user.iconData = [result dataForColumn:@"icon"];

user.name = [result stringForColumn:@"name"];

user.age = [result intForColumn:@"age"];

[users addObject:user];

}

return users;

}