Give the terms for each of the following: (a) Collection of logically related records. (b) DBMS creates a file that contains description about the data stored in the database. (c) Attribute that can uniquely identify the tuples in a relation. (d) Special value that is stored when actual data value is unknown for an attribute. (e) An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table. (f) Software that is used to create, manipulate and maintain a relational database.

Give the terms for each of the following: (a) Collection of logically related records. (b) DBMS creates a file

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Q. Give the terms for each of the following:

(a) Collection of logically related records.

(b) DBMS creates a file that contains description about the data stored in the database.

(d) Special value that is stored when actual data value is unknown for an attribute.

(e) An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table.

(f) Software that is used to create, manipulate and maintain a relational database.

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Concept understanding — Database Fundamentals

Database Fundamentals

Think of a database as a well-organised filing cabinet. In your daily life, you already manage small databases without realising it — your phone's contact list, the catalogue of a library, or even the list of students in a class register. Each of these is a collection of related information stored in a structured way so that you can find what you need quickly.

What Exactly Is a Database?

A database is a collection of related data that is stored and managed systematically. The key word here is related. A random pile of papers on a desk is not a database — but the same papers, sorted into folders with labels and a clear order, become one. The purpose of a database is to allow efficient storage, retrieval, modification, and deletion of data.

Note

A database is not the same as a spreadsheet. A spreadsheet is a single table meant for one person's use. A database is designed for multiple users, handles large volumes of data, and ensures that the data remains consistent even when many people access it at once.

Why Do We Need Databases?

Imagine a small business that keeps customer orders in a notebook. As the business grows, the notebook becomes impossible to manage — pages get lost, two customers might be given the same order number, and finding a specific order takes forever. A database solves all these problems.

Databases provide:

Centralised control — all data lives in one place, so everyone works with the same information
Data consistency — rules can be enforced (for example, an order must belong to a real customer)
Security — different users can be given different levels of access
Reduced redundancy — the same piece of information is not stored in multiple places unnecessarily
Data independence — the way data is stored can change without affecting how users view it

The Core Idea: Tables and Relationships

The most common type of database is the relational database. Think of it as a collection of tables, where each table stores information about one kind of thing.

A table is made up of rows and columns. Each column represents a field (a single piece of information, like a name or a date), and each row represents a record (one complete set of fields, like one customer's full details).

For example, a university might have a Student table with columns: Roll Number, Name, Date of Birth, and Course. Each row is one student.

The real power comes from relationships between tables. The same university might have a Course table and an Enrolment table. The Enrolment table links a student to a course using the student's roll number and the course code — without repeating all the student's details or all the course details. This is what makes a database efficient.

Important

The primary key is a column (or a set of columns) that uniquely identifies each row in a table. For the Student table, Roll Number is the primary key — no two students can share the same roll number. A foreign key is a column in one table that refers to the primary key of another table, creating the link between them.

Database Management System (DBMS)

A Database Management System is the software that lets you create, manage, and interact with a database. You do not directly touch the data files — the DBMS does that for you. Popular examples include MySQL, Oracle, and Microsoft Access.

The DBMS handles:

Data storage and retrieval — it decides how to physically store data on a disk
Query processing — when you ask for "all students born after 2005", the DBMS finds the answer
Transaction management — if two people try to book the last seat on a flight at the same time, the DBMS ensures only one succeeds
Backup and recovery — if the system crashes, the DBMS can restore the data

A Simple Example to Tie It Together

Consider a library. Without a database, the librarian keeps a card catalogue and a handwritten log of who has borrowed which book. With a database, there might be three tables:

Books (Book ID, Title, Author, ISBN, Shelf Number)
Members (Member ID, Name, Phone, Join Date)
Borrowing (Borrow ID, Book ID, Member ID, Issue Date, Return Date)

The Borrowing table uses the Book ID and Member ID to link the other two tables. To find out which books a particular member has, the DBMS looks up the Member ID in the Borrowing table, then finds the corresponding book titles from the Books table — all in a fraction of a second.

What You Should Remember

A database is not just a collection of data — it is a structured, managed, and related collection. The structure (tables, keys, relationships) is what makes it powerful. The DBMS is the tool that makes it usable. And the whole point is to store data once, keep it accurate, and retrieve it quickly whenever needed.

Note

In your exams, you will often be asked to identify tables, primary keys, foreign keys, and relationships from a given scenario. Always start by asking: What are the main "things" in this scenario? Each thing becomes a table. Then ask: How are these things connected? That connection becomes the foreign key.

Shape: Plain theory question — six definitions of database fundamentals.

(a) Collection of logically related records.

A table (or relation) is a collection of logically related records. Each record (row/tuple) shares the same structure and describes entities of the same type — for instance, all students in a Student table or all products in an Inventory table.

(b) DBMS creates a file that contains description about the data stored in the database.

The data dictionary (or system catalog) is the file that stores metadata — the description of the database structure. It holds information about table names, column names, data types, constraints, indexes, and relationships. The DBMS consults the data dictionary to interpret and enforce the schema.

(c) Attribute that can uniquely identify the tuples in a relation.

A primary key is an attribute (or set of attributes) that uniquely identifies each tuple in a relation. No two rows can have the same primary key value, and it cannot be NULL. For example, RollNo in a Student table.

(d) Special value that is stored when actual data value is unknown for an attribute.

NULL is the special marker used when the actual value of an attribute is unknown, unavailable, or not applicable. It is distinct from zero or an empty string — it represents the absence of data.

(e) An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table.

A candidate key is any attribute (or minimal set of attributes) that can uniquely identify tuples but has not been chosen as the primary key. A table may have multiple candidate keys; one is selected as the primary key, and the rest remain candidate keys. Alternatively, if the question expects the term for a candidate key that was not chosen, the answer is alternate key.

Note

Some syllabi use "candidate key" for all potential keys and "alternate key" specifically for the non-chosen ones. Both are correct in context; candidate key is the broader term.

(f) Software that is used to create, manipulate and maintain a relational database.

A Relational Database Management System (RDBMS) is the software that provides the interface and engine to create tables, insert/update/delete data, query using SQL, enforce integrity constraints, and manage transactions. Examples include MySQL, PostgreSQL, Oracle, and SQL Server.

✓Final answer

Table/Relation, Data dictionary, Primary key, NULL, (e) Candidate key (or Alternate key), (f) RDBMS.

Standard database terminology: table, data dictionary, primary key, NULL, candidate key, and RDBMS.

This is a vocabulary question testing the foundational concepts of relational database management systems. Each term represents a building block of how databases organize, describe, and enforce integrity on data. Understanding these definitions is essential before writing SQL or designing schemas.

(a) Collection of logically related records.

A table (or relation).

In the relational model, a table groups rows (records/tuples) that share the same structure and represent entities of the same type. For example, a Student table holds all student records; an Order table holds all orders. Each row is a single record, and the collection forms a logical unit.

(b) DBMS creates a file that contains description about the data stored in the database.

A data dictionary (or system catalog / metadata).

The data dictionary stores metadata: the schema definitions (table names, column names, data types, constraints, indexes). It is the "data about data." When you execute DESCRIBE Student; in MySQL or query information_schema, you are reading from the data dictionary. The DBMS itself consults this catalog to validate queries and enforce rules.

(c) Attribute that can uniquely identify the tuples in a relation.

A primary key.

The primary key is the chosen attribute (or set of attributes) that uniquely identifies every row in the table and cannot contain NULL values. For instance, StudentID in a Student table. It enforces entity integrity: no two students share the same ID, and every student must have one.

(d) Special value that is stored when actual data value is unknown for an attribute.

NULL.

NULL represents the absence of a value—not zero, not an empty string, but unknown or inapplicable. For example, if a student's phone number is not provided, the Phone column stores NULL. NULL behaves specially in SQL: NULL = NULL evaluates to unknown (not true), and aggregate functions like COUNT(column) ignore NULLs.

Watch out

NULL is not the same as zero or an empty string ''. Testing for NULL requires IS NULL or IS NOT NULL, never = NULL.

(e) An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table.

A candidate key (or alternate key).

A candidate key is any attribute (or minimal set of attributes) that could serve as a primary key—it uniquely identifies rows and contains no NULLs—but was not chosen as the primary key. For example, in a Student table, both StudentID and Email might be unique; if StudentID is the primary key, then Email is a candidate key (or alternate key). The term "alternate key" emphasizes that it is an alternative to the chosen primary key.

(f) Software that is used to create, manipulate and maintain a relational database.

An RDBMS (Relational Database Management System).

Examples include MySQL, PostgreSQL, Oracle Database, and SQLite. An RDBMS provides the engine to define schemas (DDL), insert/update/delete data (DML), query data (SELECT), enforce constraints, manage transactions, and handle concurrency. It is the software layer between the user and the physical storage of data.

✓Final answer

(a) Table (relation); (b) Data dictionary (system catalog); (c) Primary key; (d) NULL; (e) Candidate key (alternate key); (f) RDBMS (Relational Database Management System).

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