整理笔记:
1、alt + 单机 更改距离 (上下左右)
2、class 代表与谁管关联的意思
3、block 在arc 中 单独释放 block _release
4、UIPickerView 视图选择器的使用
5、数据库使用：
a、NSString *douPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];
NSString *dbPath = [douPath stringByAppendingPathComponent:@"teachers.sqlite”];
//创建数据库
db = [FMDatabase databaseWithPath:dbPath];
b、创建： NSString *createTableSql = [NSString stringWithFormat:@"create table if not exists teacher (id integer primary key autoincrement,name text,address text,age integer,salary integer)"];
BOOL result =[db executeUpdate:createTableSql] ;
c、添加：NSString *insertSql = [NSString stringWithFormat:@"insert into teacher(name,address,age,salary)values('%@','%@','%ld','%ld')",teacher.name,teacher.address,teacher.age,teacher.salary];
BOOL result =[db executeUpdate:insertSql];
d、查询：NSString *selectSql = [NSString stringWithFormat:@"select * from teacher order by salary desc"];//asc 升序 ； desc 降序
//执行查询
FMResultSet *set =[db executeQuery:selectSql];
while ([set next]) {
Teacher *tea = [[Teacher alloc]init];
tea.name = [set stringForColumn:@"name"];
tea.address = [set stringForColumn:@"address"];
tea.age = [set intForColumn:@"age"];
tea.salary = [set intForColumn:@"salary"];
[array addObject:tea];
}
e、更新：NSString *updeSql = [NSString stringWithFormat:@"update teacher set age = '40' where age = '31'"];
BOOL result =[db executeUpdate:updeSql];
f、删除： NSString *deleteSql = [NSString stringWithFormat:@"delete from teacher where salary = '700'"];
BOOL result =[db executeUpdate:deleteSql];
