В моем проекте не было ошибок, пока я не выполнил сборку.Вот журнал ошибок.
Ld "/Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Products/Debug-iphonesimulator/WC Class Codes.app/WC Class Codes" normal i386
cd "/Users/stephanieasan/Desktop/SDK Projects/WC Class Codes"
setenv MACOSX_DEPLOYMENT_TARGET 10.6
setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/clang -arch i386 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.0.sdk -L/Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Products/Debug-iphonesimulator -F/Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Products/Debug-iphonesimulator -filelist "/Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Intermediates/WC Class Codes.build/Debug-iphonesimulator/WC Class Codes.build/Objects-normal/i386/WC Class Codes.LinkFileList" -mmacosx-version-min=10.6 -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -Xlinker -no_implicit_dylibs -D__IPHONE_OS_VERSION_MIN_REQUIRED=40000 -framework iAd -lsqlite3.0 -framework UIKit -framework Foundation -framework CoreGraphics -o "/Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Products/Debug-iphonesimulator/WC Class Codes.app/WC Class Codes"
.
ld: duplicate symbol _OBJC_IVAR_$_ListTableViewController.DBPath in /Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Intermediates/WC Class Codes.build/Debug-iphonesimulator/WC Class Codes.build/Objects-normal/i386/Code.o and /Users/stephanieasan/Library/Developer/Xcode/DerivedData/WC_Class_Codes-fgxjeudpfimhnebtmvmxtzlirxnz/Build/Intermediates/WC Class Codes.build/Debug-iphonesimulator/WC Class Codes.build/Objects-normal/i386/ListTableViewController.o for architecture i386
Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/clang failed with exit code 1
Я очень смущен, я пытался отлаживать это часами безуспешно.