Write up for the sqlx db script.

_drafts/sqlx-without-macros.qmd

@@ -33,6 +33,42 @@ Because this isn't the recommended path though, the number of examples of
 using the functions online is a little lacking, which I'll make an effort
 to improve in this post.
 
-# Background
+The other thing I'll show in this post is working with JSON in Postgres.
+Postgres has native support for working with JSON documents, providing
+a lot of the benefits of NoSQL databases, but in a SQL database.
+`sqlx`'s API for json documents integrates well with serde, and is resonably
+easy to work with.
+
+# Pre-reqs
+
+Running the example requires a running Postgres database, which I'm going to run
+locally via [`podman`](https://podman.io/) using the bash script below.
+
+```bash
+#!/usr/bin/env bash
+
+DATA_DIR="$PWD/data"
+
+if [ ! -d "$DATA_DIR" ]; then
+  echo "Making data directory."
+  mkdir $DATA_DIR
+fi
+podman run --rm --name test-db --network=host \
+       -e POSTGRES_USER=postgres \
+       -e POSTGRES_PASSWORD=devpassword \
+       -e PGDATA=/var/lib/postgresql/data/pgdata \
+	   -v $DATA_DIR:/var/lib/postgresql/data \
+       docker.io/library/postgres:latest
+```
+
+The script:
+
+1. Defines `DATA_DIR` which will be a local host directory we will mount
+   in the database container and tell the database to save its files to
+   so they persist beyond container restarts.
+2. Makes that directory if it is missing.
+3. Starts a container running the official postgres image.
+   Environment variables are used to set some settings to values suitable
+   for local testing.
 
 # Example