Database Concepts
Class 11 · Informatics Practices
4 ideas in Class 11 Informatics Practices, explained in plain words, with games and quizzes to practise.
Need for Databases
Part of: Database Basics
Databases store shared data; beat files on redundancy, safety, sharing; tables organise records.
Why it matters. Shared data safe. Files beaten.
Key words
- Database
- : Organised store of shared data.
- Redundancy
- : Same data repeated in many places.
- Inconsistency
- : Copies disagreeing with each other.
- Shared access
- : Many users reaching controlled shared data.
- Database advantage
- : Less duplication with more safety.
Try it in two minutes
- Files messy?
- Share needed?
- Database built?
Try at home. List file issues.
DBMS Role
Part of: Database Basics
DBMS software manages bases; schemas define design; users query; admins guard security, backup.
Why it matters. Software manages. Admins guard.
Key words
- DBMS
- : Software that manages stored databases.
- Schema
- : Design plan fixing the database structure.
- User access
- : Queries and forms reaching stored data.
- DB admin
- : Guarding security and backups of data.
- Data independence
- : Apps shielded from storage-level changes.
Try it in two minutes
- Define schema?
- Query data?
- Guard access?
Try at home. Name DBMS tools.
Relational Tables
Part of: Tables and Keys
Relations store rows, columns; tuples are rows; attributes columns; degree counts columns.
Why it matters. Tables read. Terms known.
Formulas
- Degree = number of columns; cardinality = number of rows
- No two rows of a relation may be fully identical
Key words
- Relation
- : Table of rows and columns holding data.
- Tuple
- : One row of a database table.
- Attribute
- : One column of a database table.
- Degree
- : Column count of a table.
- Cardinality
- : Row count of a table.
- Domain
- : Allowed values set for a column.
Try it in two minutes
- Rows are tuples?
- Columns attributes?
- Degree counted?
Try at home. Draw a table.
Keys and Integrity
Part of: Tables and Keys
Primary keys identify rows; foreign keys link tables; nulls, rules guard integrity.
Why it matters. Rows identified. Links valid.
Formulas
- Primary key: unique values and never null
- Foreign key values must match real rows elsewhere
Key words
- Primary key
- : Unique never-null identifier of each row.
- Foreign key
- : Column linking to another table key.
- Candidate keys
- : Possible unique identifiers for rows.
- Null
- : Missing unknown value in a field.
- Referential integrity
- : Links matching real rows in related tables.
Try it in two minutes
- Unique key?
- Link tables?
- Guard rules?
Try at home. Key a table.
What your child will practise
- DBMS Role: Space Puzzle (Clue Puzzle)
- DBMS Role: Space Quick Fire (Quick Fire)
- Keys and Integrity: Ocean Puzzle (Clue Puzzle)
- Need for Databases: Candy Quest (Flip and Match)
- Relational Tables: Candy Quick Fire (Quick Fire)
- Quiz: DBMS Role (8 questions)
- Quiz: Keys and Integrity (8 questions)
- Quiz: Need for Databases (8 questions)
- Quiz: Relational Tables (8 questions)