Schemats

Before anything, I would like to give a massive thank you to sweetiq and their contributors for giving me a huge head start.

The reason I have created a new repo instead of a fork is because I don't support mysql and have some breaking changes due to how this library is consumed by postgres-typed and vramework.

I have kept the name and based off their MIT license as means of attribution and thanks.

Why Schemats

Because being able to make a change to your database structure and have it:

- validate through your node backend APIs
- get verified against automatically generate JSON schemas
- raise errors in your frontend application

Is just a great developer experience in my opinion.

This allows us to some pretty amazing things when it comes to refactoring and maintaining codebases, and
also provide the meta-data to help with libraries like postgres-typed.

Quickstart

$3

``bash
yarn add -d @vramework/schemats || npm install -d @vramework/schemats
`

$3

Assuming you have the following schema (this is a bit of a random one):

`sql
CREATE SCHEMA "pet_store";

CREATE TYPE "pet_store"."animal" AS enum (
'cat',
'dog'
);

CREATE TABLE "pet_store"."user" (
"uuid" uuid PRIMARY KEY default gen_random_uuid(),
"name" text NOT NULL
);

CREATE TABLE "pet_store"."pet" (
"uuid" uuid PRIMARY KEY default gen_random_uuid(),
"owner" uuid REFERENCES "pet_store"."user",
"type" pet_store.animal NOT NULL,
"name" text NOT NULL,
"birthdate" date,
"last_seen_location" point,
"random_facts" jsonb,
"pet_search_document" tsvector
);
COMMENT ON COLUMN pet_store.pet.random_facts is '@type {RandomPetFacts}';
`

You can now generate a bunch of different schema definitions.

My personal favourite is the following:

`bash
schemats postgres postgres://postgres@localhost/database -f ./db-custom-types.ts -s pet_store -c -e -o db-types.ts
`

While will result in the following typescript file:

`typescript

/**
* AUTO-GENERATED FILE @ Fri, 27 Aug 2021 08:26:50 GMT - DO NOT EDIT!
*
* This file was automatically generated by schemats v.0.0.8
* $ schemats generate postgres://username:password@localhost:5432/schemats -C -s pet_store
*
*/

import { RandomPetFacts } from './db-custom-types'

export enum Animal {
'Cat' = 'cat',
'Dog' = 'dog'
}

export interface User {
uuid: string
name: string
}

export interface Pet {
uuid: string
owner?: string | null
type: Animal
name: string
birthdate?: Date | null
lastSeenLocation?: { x: number, y: number } | null
randomFacts?: RandomPetFacts | null
moreRandomFacts?: unknown | null
petSearchDocument?: string | null
}

export interface Tables {
user: User,
pet: Pet
}

export type CustomTypes = RandomPetFacts
`

But you have quite a bit of flexbility:

`bash
Usage: schemats mysql [options] [connection]

Generate a typescript schema from mysql

Arguments:
connection The connection string to use, if left empty will use env variables

Options:
-s, --schema the schema to use (default: "public")
-t, --tables the tables within the schema
-f, --typesFile the file where jsonb types can be imported from
-c, --camelCase use camel case for enums, table names, and column names
-C, --camelCaseTypes use camel case only for TS names - not modifying the column names
-e, --enums use enums instead of types
-o, --output

where to save the generated file relative to the current working directory
--no-header don't generate a header
-h, --help display help for command

`

`bash
Generate a typescript schema from mysql

Arguments:
connection The connection string to use, if left empty will use env variables

Options:
-s, --schema the schema to use (default: "public")
-t, --tables the tables within the schema
-f, --typesFile the file where jsonb types can be imported from
-c, --camelCase use camel case for enums, table names, and column names
-C, --camelCaseTypes use camel case only for TS names - not modifying the column names
-e, --enums use enums instead of types
-o, --output

where to save the generated file relative to the current working directory
--no-header don't generate a header
-h, --help display help for command

`

Features

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This automatically turns all your tables and Enums / Types and column names to camelcase, which is the default
experience for javascript and is more consistent to use

You can use Camel Case Types to just camel case the TS entities - leaving the strings representing
the SQL columns alone.

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Using enums turns all postgres enums into Enums instead of normal types, which is just a
preference aspect for developers since renaming enum values or order will change the Enum
key and value.

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This is a VERY useful feature for jsonb fields. Normally a jsonb field type is unknown,
however if you provide a types json file this will get the type out of the comment
of a field and assign it to the value.

The structure of a custom type file could either be from another file:

`typescript
export type { RandomPetFacts } from './somewhere-else'
`

or it could just be defined straight in the file.

`typescript
export type RandomPetFacts = Record
`

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These types are automatically generated to power typed-postgres

Using in typescript

You can import all your interfaces / enums from the file:

`typescript
import * as DB from './db-types'

// And then you can start picking how you want your APIs to be used:
type updatePetLocation = Pick
`

Tests

So where are the tests? The original schemats library has an amazing 100% coverage and this one has 0.

To be honest, I'm using this library in a few of my current projects and any error in it throws dozens
in the entire codebase, so it sort of tests itself. That being said I will be looking to add some in again,
but in terms of priorties not my highest.

However for manual testing and experimenting you can easily replicate this project by:

`bash


Clone the repo

git clone git@github.com:vramework/schemats.git

Enter repo

cd schemats

Install dependencies

yarn install

Run the example, which will run create the schemats library and generate the db-types library

yarn run example:postgres
``