Cannot create an SQL store with a nil URL

[Huang-Libo]

2016-12-01 12:37:39.102201 fansky[5096:1726585] [Crashlytics] Version 3.8.3 (120)
2016-12-01 12:37:39.238837 fansky[5096:1726585] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Cannot create an SQL store with a nil URL.'
*** First throw call stack:
(0x1816721c0 0x1800ac55c 0x183933764 0x183a210b0 0x183a2e428 0x1004e521c 0x1004f1e38 0x183a1dc1c 0x183931744 0x10007e0c4 0x10007e39c 0x1000634e4 0x1000350e8 0x100034634 0x18753f100 0x18774f858 0x1877555c8 0x187769e60 0x1877525ac 0x1832198bc 0x183219728 0x183219ad0 0x181620278 0x18161fbc0 0x18161d7c0 0x18154c048 0x1875382b0 0x187533034 0x100079a9c 0x1805305b8)
libc++abi.dylib: terminating with uncaught exception of type NSException