Describe types of databases

Question 1

Relational Databases

Answer 1

Relational databases are commonly used to store and query structured data. The data is stored in tables that represent entities, such as customers, products, or sales orders. Each instance of an entity is assigned a primary key that uniquely identifies it; and these keys are used to reference the entity instance in other tables.

-They use a structured query language (SQL) for defining and manipulating the data.

Use Cases: Well-suited for applications with a fixed schema, where data integrity and relationships between tables are crucial. Examples include MySQL, PostgreSQL, and Microsoft SQL Server.

Question 2

Unrelational Databases

Answer 2

Non-relational databases are data management systems that don’t apply a relational schema to the data. Often referred to as NoSQL database, even though some support a variant of the SQL language.

There are four common types of Non-relational database commonly in use:

-Key-value databases in which each record consists of a unique key and an associated value, which can be in any format.
-Document databases, which are a specific form of key-value database in which the value is a JSON document (which the system is optimized to parse and query)
-Column-family Stores, organize data into columns rather than rows (e.g., Apache Cassandra).
-Graph databases, which store entities as nodes with links to define relationships between them.

Use Cases: Ideal for scenarios with evolving data models, large amounts of data, and distributed systems.