Does Siksha Sarovar have an AI chatbot to answer student doubts?

Yes. Siksha Sarovar has a built-in AI Assistant chatbot accessible from a floating button on every page. It understands English, Hindi and Hinglish, handles typos (for example 'pyhtion' or 'certifecate'), and indexes 165+ destinations including every course, lesson, BCA subject, school chapter, competitive exam topic, FAQ and tool. Most queries return direct link cards in under 5 milliseconds. An AI fallback is available for novel questions.

Can I ask the SikshaSarovar chatbot questions in Hindi or Hinglish?

Absolutely. The chatbot is built specifically for Indian students — natural Hinglish queries like 'kaise milega certificate', 'free hai kya', 'pyhtion ke datatype kaha hai', 'kaha se shuru karu' are first-class citizens. The matcher strips Hindi filler words and routes you to the right course, lesson or page.

Is the SikshaSarovar AI chatbot free to use?

Yes. The chatbot is 100% free, requires no signup, and is available on every page. It runs locally in your browser for the vast majority of queries — there is no API cost or usage limit. The optional 'Ask AI' fallback for advanced coding questions uses the Pro AI Tutor.

Is Siksha Sarovar really free?

Yes. Every course, lesson, quiz, online compiler, and notes download is free to use without an account. We offer an optional Pro pass that unlocks longer AI tutor sessions, larger compiler quotas and priority support, but it is not required to learn from the platform. The educational content itself stays free.

Do I need to sign in to use the courses?

No. You can browse any course, read all lessons, run code in the compiler and take quizzes without signing in. Google Sign-In is purely optional and is used only to save your progress, quiz scores and certificate eligibility across devices. We never request access to Gmail, Drive, Calendar, Contacts, or any sensitive Google data.

Are the certificates from Siksha Sarovar recognised?

Our certificates are a record of completion that you can share on LinkedIn or attach to applications, but Siksha Sarovar is an independent platform — not a UGC-recognised university or board. We are upfront about that. The certificate is most useful as a verifiable signal that you have completed the curriculum, not as a substitute for a degree.

Which courses are best for BCA and MCA students?

Our University Curriculum section covers the YMCA BCA/MCA syllabus subject-by-subject — Data Structures, DBMS, Web Based Programming, Computer Networks, Operating Systems, Software Engineering, Data Warehousing and more. Each subject is broken down into the same units your university teaches, with previous year question papers where available.

Can I use Siksha Sarovar to prepare for SSC, UPSC, Banking or Railway exams?

Yes. The Competitive section has dedicated tracks for SSC (CGL, CHSL, MTS), UPSC, IBPS/SBI Banking, RRB Railways and defence exams (NDA, CDS, AFCAT). Topics include quantitative aptitude, reasoning, English grammar, general knowledge and current affairs, written specifically for the Indian exam pattern.

What languages does the online compiler support?

The Siksha Sarovar online compiler supports C, C++, Python, Java, PHP, JavaScript, C# and SQL. The compiler runs your code in a sandboxed environment using Judge0, returns the standard output and error stream, and supports stdin so you can test interactive programs. There is no installation — everything runs in your browser.

How is my personal data handled by Siksha Sarovar?

We follow data minimisation: we collect only what is needed (email, name, profile picture from Google sign-in, and your learning progress). Data is stored on Supabase with HTTPS in transit. We do not sell user data, and we do not use it to train AI models. You can request deletion at any time by emailing contact@sikshasarovar.com — see our Privacy Policy for the full details.

Who founded Siksha Sarovar?

Siksha Sarovar was founded by Rohit Kumar, who serves as CEO and Head Developer. Rohit built the platform to provide free, structured education to students across India — covering programming courses, university notes, school study material and competitive exam preparation.

Unit 2: Handling NULL Values — Database Management Systems Notes

Siksha Sarovar

Siksha Sarovar (sikshasarovar.com) is a free educational web application that helps students in India learn programming and prepare for academic and competitive exams. The platform offers structured coding courses (C, C++, Python, Java, HTML, CSS, PHP, Power BI, AI, Machine Learning, Data Science), complete university curriculum notes for BCA/MCA students with previous year question papers, Class 10 and Class 12 CBSE/HBSE school notes, and dedicated preparation material for SSC, UPSC, Banking, Railway and other government exams. Browsing the site is completely free and requires no account. Users may optionally sign in with Google solely to save their learning progress, quiz scores and personal preferences across devices.

Unit 2: Handling NULL Values

Lesson 18 of 28 in the free Database Management Systems notes on Siksha Sarovar, written by Rohit Jangra.

18.1 What is a NULL Value?

A field with a NULL value is a field with no value. It is very important to understand that a NULL value is different from a zero value or a field that contains spaces. A NULL value is used to represent data that is missing, unknown, or not applicable.

18.2 Comparisons Using NULL

You cannot use comparison operators (like =, <, <>) with NULL.

Rule: Any arithmetic or comparison operation involving NULL results in UNKNOWN (which is effectively false for filtering).

How to Test for NULL:

To check for NULL values, use the IS NULL and IS NOT NULL operators.

Query Type	Syntax
Finding Nulls	`SELECT * FROM Emp WHERE Comm IS NULL;`
Finding Non-Nulls	`SELECT * FROM Emp WHERE Comm IS NOT NULL;`

18.3 Disallowing NULL Values

During table creation, you can specify that a column cannot accept NULL values by using the NOT NULL constraint.

18.4 Functions for NULL Handling

Most SQL dialects provide functions to handle NULLs gracefully during retrieval:

NVL(val, replacement) (Oracle)
IFNULL(val, replacement) (MySQL)
COALESCE(val1, val2, ...) (Standard SQL - returns the first non-null value).