From 2e34d6480b9baf0a30686a5f5169dd9fb66027f1 Mon Sep 17 00:00:00 2001
From: jbranchaud <jbranchaud@gmail.com>
Date: Sat, 1 Aug 2026 19:10:00 -0500
Subject: [PATCH] Add Experiment With SQLite Queries In Memory as a Python TIL

---
 README.md                                     |  3 +-
 ...xperiment-with-sqlite-queries-in-memory.md | 44 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 python/experiment-with-sqlite-queries-in-memory.md

diff --git a/README.md b/README.md
index 5ef49d8..f43523b 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1847 TILs and counting..._
+_1848 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -1093,6 +1093,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Dunder Methods](python/dunder-methods.md)
 - [Easy Key-Value Aggregates With defaultdict](python/easy-key-value-aggregates-with-defaultdict.md)
 - [Enable Pyright Type Checking In Cursor](python/enable-pyright-type-checking-in-cursor.md)
+- [Experiment With SQLite Queries In Memory](python/experiment-with-sqlite-queries-in-memory.md)
 - [Force Remaining Arguments To Be Named](python/force-remaining-arguments-to-be-named.md)
 - [Get Absolute Seconds From `timedelta` Object](python/get-absolute-seconds-from-timedelta-object.md)
 - [Get Quotient And Remainder In One Operation](python/get-quotient-and-remainder-in-one-operation.md)
diff --git a/python/experiment-with-sqlite-queries-in-memory.md b/python/experiment-with-sqlite-queries-in-memory.md
new file mode 100644
index 0000000..caf5465
--- /dev/null
+++ b/python/experiment-with-sqlite-queries-in-memory.md
@@ -0,0 +1,44 @@
+# Experiment With SQLite Queries In Memory
+
+Instead of connecting
+[`sqlite3`](https://docs.python.org/3/library/sqlite3.html) to a real file
+(database) like so:
+
+```python
+db_file: Path = data_dir / "sessions.db"
+conn: Connection = sqlite3.connect(db_file)
+```
+
+I can point it to `":memory:"`:
+
+```python
+conn: Connection = sqlite3.connect(":memory:")
+```
+
+One way this can be useful is when experimenting with some DDL (schema-modifying
+SQL statements), e.g. creating a table, adding a column, and so forth.
+
+```python
+>>> import sqlite3
+>>> conn = sqlite3.connect(":memory:")
+>>> conn.execute("""
+... create table projects (
+...     id integer primary key,
+...     name text not null unique,
+...     created_at text not null default (datetime('now')),
+...     updated_at text not null default (datetime('now'))
+... );
+... """)
+<sqlite3.Cursor object at 0x105d6e2c0>
+>>> conn.execute("insert into projects (name) values ('TIL'), ('py-vmt'), ('Pool League Pro');")
+<sqlite3.Cursor object at 0x105d6e340>
+>>> result = conn.execute("select * from projects;")
+>>> rows = result.fetchall()
+>>> rows
+[(1, 'TIL', '2026-08-01 23:59:56', '2026-08-01 23:59:56'), (2, 'py-vmt', '2026-08-01 23:59:56', '2026-08-01 23:59:56'), (3, 'Pool League Pro', '2026-08-01 23:59:56', '2026-08-01 23:59:56')]
+```
+
+This does not create any sort of on-disk version of the database. Two separate
+connections created this way will be independent in-memory database instances.
+This is technically more of [a SQLite feature](https://sqlite.org/inmemorydb.html) than a Python one, but it was in a
+Python context that I found this most useful.