我不知道这个错误在说什么。retrievePatients 方法与 WSDL 文件交互。究竟是什么错误？我要搜索什么来修复它？谢谢！
Ld /Users/chibb9/Library/Developer/Xcode/DerivedData/AllRelatedMethodsDemo-cixcxshgvqywvcgbqxcivzvomzuf/Build/Products/Debug-iphonesimulator/AllRelatedMethodsDemo.app/AllRelatedMethodsDemo normal i386
cd "/Users/chibb9/MEDiSN Research/AllRelatedMethodsDemo"
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/chibb9/Library/Developer/Xcode/DerivedData/AllRelatedMethodsDemo-cixcxshgvqywvcgbqxcivzvomzuf/Build/Products/Debug-iphonesimulator
-F/Users/chibb9/Library/Developer/Xcode/DerivedData/AllRelatedMethodsDemo-cixcxshgvqywvcgbqxcivzvomzuf/Build/Products/Debug-iphonesimulator
-filelist /Users/chibb9/Library/Developer/Xcode/DerivedData/AllRelatedMethodsDemo-cixcxshgvqywvcgbqxcivzvomzuf/Build/Intermediates/AllRelatedMethodsDemo.build/Debug-iphonesimulator/AllRelatedMethodsDemo.build/Objects-normal/i386/AllRelatedMethodsDemo.LinkFileList
-mmacosx-version-min=10.6 -Xlinker -objc_abi_version -Xlinker 2 -lxml2 -Xlinker -no_implicit_dylibs -D__IPHONE_OS_VERSION_MIN_REQUIRED=50000 -framework SystemConfiguration -framework UIKit -framework Foundation -framework CoreGraphics -o /Users/chibb9/Library/Developer/Xcode/DerivedData/AllRelatedMethodsDemo-cixcxshgvqywvcgbqxcivzvomzuf/Build/Products/Debug-iphonesimulator/AllRelatedMethodsDemo.app/AllRelatedMethodsDemo
Undefined symbols for architecture i386: "_retrievePatients", referenced from:
-[MEDiSN20AidnWebServiceRunner run] in MEDiSN20AidnWebServiceRunner.o "_OBJC_METACLASS_$_NSManagedObject", referenced from:
_OBJC_METACLASS_$_Download in Download.o "_OBJC_CLASS_$_NSManagedObject", referenced from:
_OBJC_CLASS_$_Download in Download.o ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation)