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Questions and Answers
What is the main purpose of database modelling?
What is the main purpose of database modelling?
In which normal form does a table ensure that non-key attributes are fully dependent on the primary key?
In which normal form does a table ensure that non-key attributes are fully dependent on the primary key?
What does the Third Normal Form (3NF) ensure in a table?
What does the Third Normal Form (3NF) ensure in a table?
Which technique is used to split tables into smaller, more manageable units in database modelling?
Which technique is used to split tables into smaller, more manageable units in database modelling?
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What is the purpose of Entity-Relationship Model in database design?
What is the purpose of Entity-Relationship Model in database design?
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Which aspect of database modelling focuses on how data is organized within a database system?
Which aspect of database modelling focuses on how data is organized within a database system?
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What is the purpose of data modeling in the database design process?
What is the purpose of data modeling in the database design process?
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What do entities represent in the Entity-Relationship (ER) model?
What do entities represent in the Entity-Relationship (ER) model?
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What does a database schema define?
What does a database schema define?
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In database design, what does query design primarily involve?
In database design, what does query design primarily involve?
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What is the main goal of database design?
What is the main goal of database design?
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Which technique is crucial for ensuring data integrity, consistency, and security in a database system?
Which technique is crucial for ensuring data integrity, consistency, and security in a database system?
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Study Notes
Database Modelling
Database modelling is the process of creating a data structure for a database system. It involves designing the structure of the database, its relationships, and the way data is organized. This process helps to ensure data consistency, integrity, and security. In this article, we will discuss the various aspects of database modelling, including normalization, data modeling, entity-relationship model, database schema, database design, and query design.
Normalization
Normalization is a technique used to eliminate redundancies and ensure the integrity of data in a database. It involves splitting tables into smaller, more manageable units, each containing only indivisible values. There are five normal forms, but in practice, only the first three are commonly used to achieve sufficient data integrity and consistency.
- First Normal Form (1NF): Each attribute must contain a single indivisible value. Compound data, such as addresses, are subdivided into separate attributes: street, city, and country.
- Second Normal Form (2NF): A table is in 2NF if it is in 1NF and each non-key attribute is fully dependent on the primary key.
- Third Normal Form (3NF): A table is in 3NF if it is in 2NF and there are no transitive dependencies, meaning the relationship between non-key attributes is not dependent on the primary key.
Normalization helps to eliminate redundancy and ensure that the data in the database is consistent and reliable. It is an important step in the database design process.
Data Modeling
Data modeling is the process of creating a visual representation of either a whole information system or parts of it. It helps to illustrate the types of data used and stored within the system, the relationships among these data types, the ways the data can be grouped and organized, and its formats and attributes. Data models are built around business needs.
Entity-Relationship Model
The Entity-Relationship (ER) model is a widely used data modeling technique that helps developers to identify and describe the entities, attributes, and relationships between them. The ER model uses entities, which represent data objects, and relationships, which connect entities. The relationships are shown as lines connecting the entities.
Database Schema
A database schema is a logical framework that defines the structure of the database. It provides a way to organize and represent data in the database. A schema includes tables, views, indexes, and other database objects.
Database Design
Database design is the process of creating a database schema. It involves defining the tables, columns, relationships, and constraints that will be used in the database. The goal is to create a database that can efficiently store, retrieve, and manipulate data.
Query Design
Query design is the process of creating SQL queries that retrieve data from the database. Queries are designed to extract specific information from the database and can be used for reporting, analysis, and other data-driven tasks.
In conclusion, database modelling is a crucial aspect of creating and maintaining a database system. It involves various techniques and processes, including normalization, data modeling, entity-relationship modeling, database schema design, and query design. These techniques help ensure data integrity, consistency, and security, making the database a valuable tool for businesses and organizations.
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Description
Test your knowledge on database modelling techniques including normalization, data modeling, entity-relationship model, database schema, database design, and query design. Learn about the importance of ensuring data integrity, consistency, and security in databases.
