Basic Terminologies in DBMS - SS3 ICT Lesson Note

Basic Terminologies in DBMS:

• Database: A structured collection of data organized for efficient retrieval and manipulation.

 

• Table: A fundamental structure in a relational database that organizes data into rows and columns.

 

• Record or Row: A single entry or data instance in a table, representing a unique entity.

 

• Field or Column: A specific data attribute or characteristic within a table, such as a name, age, or address.

 

• Primary Key: A unique identifier for each record in a table, ensuring data integrity and facilitating data retrieval.

 

• Foreign Key: A field that establishes a link between tables by referencing the primary key of another table, enabling relationships between data.

 

• Query: A request to retrieve, manipulate, or analyze data from a database, often written in SQL (Structured Query Language).

 

• Normalization: The process of organizing data in a database to minimize redundancy and ensure data integrity by breaking it into smaller related tables.

 

• Transaction: A sequence of one or more SQL operations treated as a single unit of work, ensuring data consistency and integrity.

 

• ACID (Atomicity, Consistency, Isolation, Durability): A set of properties that guarantee the reliability of database transactions. ACID stands for Atomicity, Consistency, Isolation, and Durability, and they are critical for ensuring the reliability of database transactions:

1. Atomicity: This property ensures that a transaction is treated as a single unit of work. It either completes entirely or leaves no trace if it fails, preventing partial changes to the database, which could lead to inconsistencies.
2. Consistency: It guarantees that a transaction brings the database from one consistent state to another. It enforces data integrity constraints, ensuring that only valid data changes occur.
3. Isolation: Isolation ensures that concurrent transactions do not interfere with each other. Each transaction appears to be executed in isolation from others, preventing data corruption due to simultaneous access.
4. Durability: Durability guarantees that once a transaction is committed, its effects are permanent and survive system failures. It ensures that data changes are not lost.