问题
I have managed objects that have image properties. Since storing large blobs in CoreData is a bad idea, I'm trying to use the built-in CoreData option "Store in External Record File" which you can see in the Data Model Inspector.
Despite enabling this option, I do not see any image data being stored externally. Judging by the size, it seems like they are still being saved in the sqlite file. What is the issue?
回答1:
If your store type is NSSQLiteStoreType, your attribute is NSBinaryDataAttributeType. You have enabled setAllowsExternalBinaryDataStorage and your object data size is larger then approximately 1MB.
- Objects that are smaller than 1MB are stored in the sqlite database.
- Objects that are larger are just a reference to a external file.
You'll find the (external) files in a hidden sub-directory at the same location as the persistent store.
<path>/<database>.sqlite
<path>/<your_database>_SUPPORT/_EXTERNAL_DATA/
回答2:
sqlite2 does not allow size of BLOB data to be more than 1MB,However sqlite 3 allows larger BLOB.First check out which version of sqlite u r using. And if ur file is in MB's i would rather prefer them storing in local database instead.
来源：https://stackoverflow.com/questions/9801944/storing-blobs-in-external-location-using-built-in-coredata-option