Hi

I will answer your question in parts.

HOW CAN YOU APPEAR FOR UPSC CIVIL SERVICES EXAM AFTER BCA

You can definitely appear for UPSC with qualification of BCA.

This is because,

To be eligible for UPSC examination there's no need to be a graduate in a particular discipline,  all you need to be is a graduate in any discipline from a recognised university be it  BCA or any  other graduation course.

So, you don't worry with BCA  degree you will be eligible for UPSC

You can check UPSC eligibility  criteria provided below:-

*You  must  have  a bachelor's  degree in any, discipline    from a  recognised university.

*Minimum  age  limit :-  you  need to  be at least  21  years  old   to be  eligible.

*Maximum  age  limit :-  32 years , also there's 3  year  relaxation on upper age limit for  obc and of  5 years  for sc/st category.

For detailed  information related to UPSC eligibility criteria ,  you can visit our page at

https://competition.careers360.com/articles/upsc-ias-eligibility-criteria/amp

WILL EXAM HAVE BCA SUBJECTS

No,  in UPSC civil service examination you don't have your BCA subjects i. e Database Management Systems, Computer Networks etc rather you have to prepare for subjects like  history polity etc. You can get the complete syllabus at

https://competition.careers360.com/articles/upsc-ias-syllabus/amp

But yes,

You are free to choose optional subjects of your choice from the available options. So, being BCA student you may choose for MATHS as optional or any other subject of your choice.

List of optional subject is provided below:-

-) Agriculture

-) Animal Husbandry and Veterinary Science

-) Anthropology

-) Botany

-) Chemistry

-) Civil Engineering

-) Commerce & Accountancy

-) Economics

-) Electrical Engineering

-) Geography

-) Geology

-) History

-) law

-) Management

-) Mathematics

-) Mechanical Engineering

-) Medical Science

-) Philosophy

-) Physics

-) Political Science & International Relations

-) Psychology

-)Public Administration

-) Sociology

-)Statistics

-) Zoology

List of literature optional subjects is provided below:

-) English

-) Assamese

-) Bengali

-) Gujarati

-) Hindi

-) Kannada

-) Kashmiri

-) Konkani

-) Malayalam

-) Manipuri

-) Marathi

-) Nepali

-) Odia

-) Punjabi

-) Sanskrit

-) Sindhi

-) Tamil

-) Telugu

-) Urdu

-) Bodo

-) Dogri

-) Maithili

-) Santhali

To help you for further, here's a brief of UPSC civil services examination pattern.

UPSC civil services examination  has 3 stages listed below :-

*prelims exam :- it is objective paper and is of qualifying nature , so you just  need to at least qualify it to be eligible for mains examination, the score /marks obtained by you in your prelims examination is not added up or used in your final merit. Your prelims exam consist of 2 papers: -

-) general studies 1

-) general studies II ( csat )

You get 2 hours for each paper

*Mains exam. :- it is descriptive /written examination . There are a total of 9 papers  which are listed below:-

-) paper A :- compulsory indian language.

-) paper B :- english

-) essay

-) general studies I

-) general studies II

-) general studies III

-) general studies IV

-) optional I

-) optional II

*Interview

https://competition.careers360.com/articles/upsc-ias-exam-pattern

Thank you