Comprehensive Notes on Computerised
Databases and Presentation Software
3.1 Computerised Database User Requirements Collection
3.1.1 Introduction to Database
3.1.1.1 Key Concepts
• Database: An organized collection of data stored electronically to support efficient
access, retrieval, and management.
• Database Management System (DBMS): Software tools that enable users to create,
read, update, and delete data in databases while enforcing security, integrity, and
concurrency.
• Data: Raw, unprocessed facts like numbers, text, or images.
• Information: Processed data that has been organized or interpreted to be meaningful and
useful.
• Users: People who interact with the database, including:
o End Users: Use the database for daily tasks.
o Database Administrators (DBA): Manage and maintain the database.
o Developers: Design and implement databases and applications.
3.1.1.2 Database Organisation
• Databases are structured to allow data to be stored, organized, and accessed efficiently.
• Types of database organisations:
o Flat-file databases: Simple, single table format, suitable for small data sets, lacks
complex relationships.
o Hierarchical databases: Data organized in a tree-like structure with parent-child
relationships; fast but inflexible.
o Network databases: Allows many-to-many relationships using a graph structure.
o Relational databases: Data stored in tables (relations) with rows and columns;
uses keys to define relationships; most widely used.
o Object-oriented databases: Store data as objects, which encapsulate both data
and behaviors; useful for complex data types.
3.1.1.3 Database Relationships
• Define how data entities are connected:
, o One-to-One (1:1): Each record in Table A corresponds to exactly one record in
Table B. Rare but useful in sensitive data partitioning.
o One-to-Many (1:M): One record in Table A can be associated with many records
in Table B (e.g., one customer with many orders).
o Many-to-Many (M:N): Multiple records in Table A relate to multiple records in
Table B, implemented via junction tables (e.g., students and courses).
3.1.1.4 Database Operations
• Basic CRUD operations performed on databases:
o Create: Adding new tables, records, or fields.
o Read: Retrieving data via queries.
o Update: Changing existing data values.
o Delete: Removing data or structures.
• Other operations:
o Querying: Asking complex questions to filter and extract specific data.
o Sorting and Filtering: Organizing data according to specific criteria.
o Joining: Combining data from multiple tables.
3.1.2 Collection of User Requirements
• Essential for building a database tailored to user needs.
• Methods of collection:
o Interviews: Direct discussions with stakeholders.
o Questionnaires: Standardized forms for data gathering.
o Observation: Watching how users interact with existing systems.
o Document Analysis: Reviewing existing records and reports.
• Focus on understanding:
o Data to be stored (types, volume, formats).
o Frequency and purpose of data access.
o Security and access controls.
o Reporting and output needs.
o User roles and permissions.
o Performance expectations (speed, concurrency).
3.2 Design Computerised Database Schema
3.2.1 Creating Database Models
3.2.1.1 ERD Models (Entity-Relationship Diagrams)
• Used during the design phase to visually represent data.
Databases and Presentation Software
3.1 Computerised Database User Requirements Collection
3.1.1 Introduction to Database
3.1.1.1 Key Concepts
• Database: An organized collection of data stored electronically to support efficient
access, retrieval, and management.
• Database Management System (DBMS): Software tools that enable users to create,
read, update, and delete data in databases while enforcing security, integrity, and
concurrency.
• Data: Raw, unprocessed facts like numbers, text, or images.
• Information: Processed data that has been organized or interpreted to be meaningful and
useful.
• Users: People who interact with the database, including:
o End Users: Use the database for daily tasks.
o Database Administrators (DBA): Manage and maintain the database.
o Developers: Design and implement databases and applications.
3.1.1.2 Database Organisation
• Databases are structured to allow data to be stored, organized, and accessed efficiently.
• Types of database organisations:
o Flat-file databases: Simple, single table format, suitable for small data sets, lacks
complex relationships.
o Hierarchical databases: Data organized in a tree-like structure with parent-child
relationships; fast but inflexible.
o Network databases: Allows many-to-many relationships using a graph structure.
o Relational databases: Data stored in tables (relations) with rows and columns;
uses keys to define relationships; most widely used.
o Object-oriented databases: Store data as objects, which encapsulate both data
and behaviors; useful for complex data types.
3.1.1.3 Database Relationships
• Define how data entities are connected:
, o One-to-One (1:1): Each record in Table A corresponds to exactly one record in
Table B. Rare but useful in sensitive data partitioning.
o One-to-Many (1:M): One record in Table A can be associated with many records
in Table B (e.g., one customer with many orders).
o Many-to-Many (M:N): Multiple records in Table A relate to multiple records in
Table B, implemented via junction tables (e.g., students and courses).
3.1.1.4 Database Operations
• Basic CRUD operations performed on databases:
o Create: Adding new tables, records, or fields.
o Read: Retrieving data via queries.
o Update: Changing existing data values.
o Delete: Removing data or structures.
• Other operations:
o Querying: Asking complex questions to filter and extract specific data.
o Sorting and Filtering: Organizing data according to specific criteria.
o Joining: Combining data from multiple tables.
3.1.2 Collection of User Requirements
• Essential for building a database tailored to user needs.
• Methods of collection:
o Interviews: Direct discussions with stakeholders.
o Questionnaires: Standardized forms for data gathering.
o Observation: Watching how users interact with existing systems.
o Document Analysis: Reviewing existing records and reports.
• Focus on understanding:
o Data to be stored (types, volume, formats).
o Frequency and purpose of data access.
o Security and access controls.
o Reporting and output needs.
o User roles and permissions.
o Performance expectations (speed, concurrency).
3.2 Design Computerised Database Schema
3.2.1 Creating Database Models
3.2.1.1 ERD Models (Entity-Relationship Diagrams)
• Used during the design phase to visually represent data.
