eolas/Databases/ACID_principle.md

---
categories:
  - Databases
tags: [relational-databases]
---

# ACID principle

> A database is a collection of organised data that can be efficiently stored,
> sorted, and searched.

How the data is organised will often determine the _type_ of database used.
There are many different types of database; some examples of the different types
are relational, object-orientated, graphical, NoSQL, and distributed. All should
meet the principles of ACID.

To ensure the integrity of a database, each change or transaction must conform
to a set of rules known as ACID:

- **atomicity**
  - when changing data within a database, if any part of the change fails, the
    whole change will fail and the data will remain as it was before the change
    was made; this is a safeguard that prevents partial records being created.
- **consistency**
  - before data can be changed in a database, it must be validated against a set
    of rules
- **isolation**
  - databases allow multiple changes at the same time, but each change is
    isolated from others
- **durability**
  - once a change has been made, the data is safe, even in the event of system
    failure

> Databases will have mechanisms for **backup**, **distribution**, and
> **redundancy**, to ensure data is not lost.
Initial commit, pure MD 2022-04-23 13:26:53 +01:00			`---`
Restructure cats and tags 2022-08-16 11:58:34 +01:00			`categories:`
Initial commit, pure MD 2022-04-23 13:26:53 +01:00			`- Databases`
Autosave: 2023-02-10 18:22:04 2023-02-10 18:22:04 +00:00			`tags: [relational-databases]`
Initial commit, pure MD 2022-04-23 13:26:53 +01:00			`---`

More diagrams, SQL notes 2022-12-08 20:18:56 +00:00			`# ACID principle`
Last Sync: 2022-08-05 09:00:04 2022-08-05 09:00:04 +01:00
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`> A database is a collection of organised data that can be efficiently stored,`
			`> sorted, and searched.`
Initial commit, pure MD 2022-04-23 13:26:53 +01:00
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`How the data is organised will often determine the _type_ of database used.`
			`There are many different types of database; some examples of the different types`
			`are relational, object-orientated, graphical, NoSQL, and distributed. All should`
			`meet the principles of ACID.`
Initial commit, pure MD 2022-04-23 13:26:53 +01:00
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`To ensure the integrity of a database, each change or transaction must conform`
			`to a set of rules known as ACID:`
Initial commit, pure MD 2022-04-23 13:26:53 +01:00
Restructure cats and tags 2022-08-16 11:58:34 +01:00			`- atomicity`
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`- when changing data within a database, if any part of the change fails, the`
			`whole change will fail and the data will remain as it was before the change`
			`was made; this is a safeguard that prevents partial records being created.`
Restructure cats and tags 2022-08-16 11:58:34 +01:00			`- consistency`
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`- before data can be changed in a database, it must be validated against a set`
			`of rules`
Restructure cats and tags 2022-08-16 11:58:34 +01:00			`- isolation`
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`- databases allow multiple changes at the same time, but each change is`
			`isolated from others`
Restructure cats and tags 2022-08-16 11:58:34 +01:00			`- durability`
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`- once a change has been made, the data is safe, even in the event of system`
			`failure`
Restructure cats and tags 2022-08-16 11:58:34 +01:00
reformat all files to 80 char line length 2024-02-02 15:58:13 +00:00			`> Databases will have mechanisms for backup, distribution, and`
			`> redundancy, to ensure data is not lost.`