Merge pull request #398 from itsHobbes/master

feat: add sqlite spotlight
2026-09-04 09:15:58 +02:00 · 2021-04-27 06:20:10 -04:00
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+## What is SQLite?
+
+Sqlite is a small self-contained SQL database engine written in ANSI C. It allows for creating an SQL database both on disk as a single file, and in memory.
+It is commonly embedded either into an operating system or an application to store data for querying against without running a full DBMS.
+
+Sqlite has some rather attractive features that make it a good choice for many situations, those situations include; 
+- Storing a cache of data between application runs.
+- Storing relational data for querying either on disk or in ram.
+- Being used as a stable format for long term storage.
+
+This being said, Sqlite does have a few usecases it is unsuited for;
+- Being accessed directly by multiple users over the network.
+- Petabyte scale data.
+- Highly concurrent reads and writes.
+
+## Standout Features
+
+Sqlite is small, simple and consistent. They make promises to maintain backwards compatibility and have a well worked and simple codebase. 
+
+There are about 138 thousand lines of code (not counting blank lines or comments), but over 91946 thousand lines of testing code, 
+this means that it is probably one of the most tested pieces of software currently used today.
+Its so well tested and trusted that its used in the Airbus A350, which means its trusted to an Aviation-grade.
+Its built in limits are huge, Sqlite can support databases upto 140 terabytes in size with around a gigabyte per row.
+Sqlite is entirely public domain and requires no changes to licensing for embedding, reselling, repackaging, or modifying in anyway.
+It comes standard in a few programming languages like Python and PHP, and has out the box bindings for C/C++/TCL. 
+Even the US Library of Congress uses it as a suitable long term data storage format.
+Sqlite can even be extended to support JSON and other functionality.
+
+Sqlite is probably the most deployed database in the world, every Android, iOS, Mac, Windows 10 install has an Sqlite database running somewhere in it,
+its also widely used in many commercial software projects like; Skype, iTunes, Firefox, Chrome, Safari, Dropbox, TurboTax and so many more.
+This probably accounts for billions if not trillions of installations around the world.
+
+## Basic Usage
+
+Lets get started on some basic usage. Im going to keep things very simple.
+For these examples we will use the command line tool `sqlite3`
+Lets fire it up `sqlite3`
+
+```
+SQLite version 3.28.0 2019-04-16 19:49:53
+Enter ".help" for usage hints.
+sqlite>
+```
+
+Before we start lets turn on some helpers (they make output prettier) 
+```
+.headers on
+.mode column
+```
+
+
+In here we can now execute our SQL commands.
+
+First we will create some tables
+
+```sql
+create table artist
+(
+    id   integer
+        constraint artist_pk
+            primary key autoincrement,
+    name text not null
+);
+
+create unique index artist_id_uindex
+    on artist (id);
+
+create table song
+(
+    id        integer
+        constraint song_pk
+            primary key autoincrement,
+    title     text not null,
+    artist_id int  not null
+        constraint artist_id
+            references artist
+);
+
+create unique index song_id_uindex
+    on song (id);
+```
+
+This will create a simple database with two tables. Song and Artist, there is also a relationship between a song and its artist
+
+Lets insert some data into the database now,
+```sql 
+INSERT INTO artist (id, name)
+VALUES (1, 'Billie Eilish');
+INSERT INTO artist (id, name)
+VALUES (2, 'The Jackson 5');
+INSERT INTO artist (id, name)
+VALUES (3, 'The Beatles');
+
+INSERT INTO song (id, title, artist_id)
+VALUES (1, 'Bad Guy', 1);
+INSERT INTO song (id, title, artist_id)
+VALUES (2, 'I Want You Back', 2);
+INSERT INTO song (id, title, artist_id)
+VALUES (3, 'Hey Jude', 3);
+INSERT INTO song (id, title, artist_id)
+VALUES (4, 'Eleanor Rigby', 3);
+INSERT INTO song (id, title, artist_id)
+VALUES (5, 'Let It Be', 3);
+```
+
+Now we can start querying the database. First lets get all the songs. 
+
+```sql
+select * from song;
+```
+We will get back 
+
+```
+sqlite> select * from song;
+id          title       artist_id
+----------  ----------  ----------
+1           Bad Guy     1
+2           I Want You  2
+3           Hey Jude    3
+4           Eleanor Ri  3
+5           Let It Be   3
+```
+
+Now lets do a more complex query with a join in it, to get the relation data. Lets get all the songs by The Beatles.
+
+```sql
+select song.id as song_id, artist.name as artist_name, song.title as title
+FROM song
+         join artist on song.artist_id = artist.id
+WHERE (select artist_id from artist where artist_name = 'The Beatles');
+```
+
+This should return something like 
+```
+sqlite> song_id     artist_name  title
+   ...> ----------  -----------  ----------
+   ...> 3           The Beatles  Hey Jude
+   ...> 4           The Beatles  Eleanor Ri
+   ...> 5           The Beatles  Let It Be
+   ...>
+```
+
+Other than that this is a fully fledged SQL engine, so you can go to town trying to create whatever relational data you want inside it.
+
+## Resources
+
+* When to use SQLite: https://www.sqlite.org/whentouse.html
+* Documentation: https://www.sqlite.org/docs.html
+