新建一个基于CRecordset的类，为什么会出现这样的错误啊

[duhualin]

------------------Configuration: dada - Win32 Debug--------------------
Compiling...
sdas.cpp
f:\myproject\dada\sdas.h(14) : error C2504: 'CRecordset' : base class undefined
f:\myproject\dada\sdas.h(16) : error C2629: unexpected 'class sdas ('
f:\myproject\dada\sdas.h(16) : error C2238: unexpected token(s) preceding ';'
f:\myproject\dada\sdas.h(32) : error C2061: syntax error : identifier 'CFieldExchange'
F:\myproject\dada\sdas.cpp(17) : error C2653: 'CRecordset' : is not a class or namespace name
F:\myproject\dada\sdas.cpp(17) : error C2065: 'classCRecordset' : undeclared identifier
F:\myproject\dada\sdas.cpp(19) : error C2065: 'CDatabase' : undeclared identifier
F:\myproject\dada\sdas.cpp(19) : error C2065: 'pdb' : undeclared identifier
F:\myproject\dada\sdas.cpp(20) : error C2448: '<Unknown>' : function-style initializer appears to be a function definition
F:\myproject\dada\sdas.cpp(20) : error C2143: syntax error : missing ';' before ':'
F:\myproject\dada\sdas.cpp(21) : error C2448: '<Unknown>' : function-style initializer appears to be a function definition
F:\myproject\dada\sdas.cpp(41) : error C2065: 'CFieldExchange' : undeclared identifier
F:\myproject\dada\sdas.cpp(41) : error C2065: 'pFX' : undeclared identifier
F:\myproject\dada\sdas.cpp(42) : error C2448: '<Unknown>' : function-style initializer appears to be a function definition
F:\myproject\dada\sdas.cpp(56) : error C2653: 'CRecordset' : is not a class or namespace name
F:\myproject\dada\sdas.cpp(61) : error C2653: 'CRecordset' : is not a class or namespace name
Error executing cl.exe.

dada.exe - 16 error(s), 0 warning(s)