Rename Operation

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/BPSC/database-systems/relational-algebra/rename-operation/asset-rename-operation after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Section 1 | Language (Hindi): भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, संधि, समास, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), वर्णमाला
  3. Section 1 | Language (उर्दू भाषा — 22 प्रश्न (निश्चित)): Spelling & Diacritics, Grammar (اسم, فعل, صفت, ضمیر), Vocabulary, Idioms & Proverbs, Comprehension
  4. Section 1 | Language (বাংলা / बांग्ला भाषा — 22 प्रश्न (निश्चित)): Bangla Script and Sounds, Bangla Grammar and Usage, Bangla Word Formation and Vocabulary, Reading and Text Interpretation
  5. Section 1 | Language (English): Vocabulary, Noun, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Tenses, Pronoun, Verb, Adverb, Preposition, Articles, Determiner, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Construction, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Verbal Analogy (Word Based Analogy), Facts, Inference and Judgements
  6. Section 2 | Primary Maths & Reasoning: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Percentage, Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Mensuration and Geometry, Age Problems, Arithmetic, Powers and Exponents (Surds and Indices), Algebra, Probability, Trigonometry, Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence
  7. Section 2 | General Awareness (GK + Current Affairs): Polity, Physics, Biology, State Wise GK, Chemistry, History, Geography, Indian Economy, Environment, GK- Current Affairs, Static General Knowledge
  8. Section 3 | Computer System and Org. (CSO): Basics of COA, Floating Point Rep, Cache Memory Organization, Instr Formats & Modes, Programming the Basic Computer, Input Output Organisation, Register Transfer and Microoperations, Control Unit Design
  9. Section 3 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control
  10. Section 3 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Process Synchronization
  11. Section 3 | Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics
  12. Section 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Minimum Spanning Trees, Shortest Path Algos
  13. Section 3 | Theory Of Computation & Compiler Design: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization
  14. Section 3 | Emerging Trends (AI, Societal Ethics & MS Office): Artificial Intelligence, Emerging Tech Trends, Society, Law & Ethics, MS Office Applications
  15. Section 3 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Maintenance and Configuration Management, Software Testing
  16. Section 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Section 3 | OOPS, C++, JAVA, HTML: OOPS with C++, Java, HTML Basics, CSS
  18. Section 3 | Java: Java Fundamentals, Array, String, IO & References
  19. Section 3 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  20. Section 3 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  21. Section 3 | Multimedia: Multimedia
  22. BPSC Previous Year Papers:
  23. BPSC Full Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment introduces the Rename operation in Relational Algebra, denoted by the Greek letter rho ($

ho$), which assigns a name to the result of an expression. The instructor demonstrates its syntax and utility through two distinct examples: first, calculating a total amount with interest and renaming the resulting table, and second, finding the maximum loan amount using a self-join and set difference operation.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by explaining that results of relational algebra operations are relations but lack names. To address this, he introduces the Rename operation, denoted by the small Greek letter rho ($ ho$). He writes the formal syntax on the board: $ ho_{X(A1, A2, A3, A4, ..., AN)}(E)$. Here, $E$ represents the expression whose result is being named, and $X$ is the new name assigned to that relation. The attributes $A1$ through $AN$ represent the new column names. He illustrates this concept by writing 'find student' on the board, showing how a relation could be renamed to 'student' with specific attributes, emphasizing that this operation is essential for referencing intermediate results in complex queries.

  2. 2:00 – 5:00 02:00-05:00

    The lecture transitions to a practical problem: 'Write a RELATIONAL ALGEBRA query to find the account_no along with balance with 8% interest as total amount, with table name as balance sheet?'. The instructor identifies the 'account' table as the source. He constructs a projection $\Pi$ to select the account number and calculate the new balance column using the formula $balance imes 1.08$. He then applies the rename operator to this projection, writing $ ho_{balance\_sheet(account\_no, total\_amount)}$. This step assigns the name 'balance_sheet' to the resulting relation and explicitly names the columns 'account_no' and 'total_amount', demonstrating how to combine calculation, selection, and renaming in a single query structure.

  3. 5:00 – 6:19 05:00-06:19

    The final segment addresses a more complex query: 'Write a RELATIONAL ALGEBRA query to find the loan_no with maximum loan amount?'. The instructor explains that finding a maximum value typically requires comparing every record against every other record. He writes a self-join using the Cartesian product: $ ho_A(loan) imes ho_B(loan)$, where the loan table is renamed to A and B. He then constructs a selection $\sigma_{A.loan\_amount < B.loan\_amount}$ to find pairs where one loan is smaller than another. By subtracting these smaller loans from the original set of loan numbers using set difference, he isolates the loan number that is not smaller than any other, effectively finding the maximum. He draws a small numerical table (10, 20, 30) to visually demonstrate which pairs are eliminated during this process.

The video effectively bridges theoretical definitions with practical application. It starts by defining the Rename operation as a necessary tool for naming unnamed relational results. It then immediately applies this to a financial calculation example, showing how to compute new values and name the output table. Finally, it escalates the complexity by introducing the set difference operator combined with a self-join to solve a 'maximum' problem, illustrating that relational algebra can handle complex logic like finding extrema through set operations rather than just simple filtering.

Loading lesson…