CoreData Persistence data store attention points

CoreData is an important means to implement data persistence storage after iOS3.0. Here are some points to note:

1. appdelegate

2. coredata entity creation can not be used alloc, but need to use nsentitydescription

3. coredata needs to be synchronized after each operation, that is, save

4. add

   nsentitydescription: Method:

+ (ID) insertnewobjectforentityforname: (NSString *) entityname inmanagedobjectcontext: (Nsmanagedobjectcontext *) Context

5. Check

Nsfetchrequest Data Query Request class

Nspredicate set query criteria through predicates, not set to get all data

6. Delete, change

Build on the basis of the check, through the query to get the array, delete it or change the operation ...

CoreData Persistence data store attention points