Add README

Author: onozaty

README.md

@@ -1,3 +1,235 @@
 # prisma-db-comments-generator
 
-Generate database comments from Prisma schema.
+Generate database comments from Prisma schema.
+
+It is based on the following code idea. Thank you @Jyrno42 .
+
+- https://github.com/prisma/prisma/issues/8703#issuecomment-1614360386
+
+## Features
+
+- Create a migration SQL for the `COMMENT ON` statement based on the information in the `schema.prisma` file.
+    - Comments written with triple slashes (`///`) are eligible.
+- Create a `COMMENT ON` statement only for the part of the difference.
+    - The previous information is stored as `prisma/migrations/comments-latest.json`.
+- Support for table and column comments.
+- Comments you do not want to create can be excluded using regular expressions.
+    - For example, a VIEW is to be created manually, and you do not want to create a comment statement from the `schema.prisma`. In such cases, you can exclude them by specifying the pattern of the VIEW.
+- Enum information can be added to column comments.
+
+## Usage
+
+Install this package.
+
+```
+npm install --save-dev @onozaty/prisma-db-comments-generator
+```
+
+Add the generator to the `schema.prisma`
+
+```prisma
+generator comments {
+  provider = "prisma-db-comments-generator"
+}
+```
+
+Run `npx prisma generate` to trigger the generator.
+A SQL file for `COMMENT ON` is generated in the migrations folder.
+
+```
+$ npx prisma generate
+Environment variables loaded from .env
+Prisma schema loaded from prisma/schema.prisma
+Comments generation completed: 20240804142142_update_comments
+
+✔ Generated Prisma Client (v5.17.0) to ./node_modules/@prisma/client in 73ms
+
+✔ Generated Prisma Database Comments (v1.0.1) to ./prisma/migrations in 11ms
+```
+
+## Example
+
+For example, from the following `schema.prisma`,
+
+```prisma
+generator client {
+  provider = "prisma-client-js"
+}
+
+generator comments {
+  provider = "prisma-db-comments-generator"
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+/// Product type enumeration
+enum ProductType {
+  BOOK
+  TOY
+  FASHION
+
+  @@map("enum_product_type")
+}
+
+/// Customer
+model Customer {
+  /// Customer ID
+  customerId Int      @id @default(autoincrement()) @map("customer_id")
+  /// Customer Name
+  name       String
+  /// e-mail
+  email      String   @unique
+  createdAt  DateTime @default(dbgenerated("statement_timestamp()")) @map("created_at") @db.Timestamptz()
+  sales      Sale[]
+
+  @@map("customers")
+}
+
+/// Product
+model Product {
+  /// Product ID
+  productId   Int         @id @default(autoincrement()) @map("product_id")
+  /// Product Name
+  name        String
+  /// Product Type
+  type        ProductType
+  /// Product Description
+  description String?
+  /// Price
+  price       Float
+  createdAt   DateTime    @default(dbgenerated("statement_timestamp()")) @map("created_at") @db.Timestamptz()
+  sales       Sale[]
+
+  @@map("products")
+}
+
+model Sale {
+  /// Sale ID
+  saleId     Int      @id @default(autoincrement()) @map("sale_id")
+  customer   Customer @relation(fields: [customerId], references: [customerId])
+  /// Customer ID
+  customerId Int      @map("customer_id")
+  product    Product  @relation(fields: [productId], references: [productId])
+  /// Product ID
+  productId  Int      @map("product_id")
+  /// Quantity
+  quantity   Int
+  /// Total Price
+  totalPrice Float    @map("total_price")
+  createdAt  DateTime @default(dbgenerated("statement_timestamp()")) @map("created_at") @db.Timestamptz()
+
+  @@map("sales")
+}
+```
+
+A migration SQL file will be generated as shown below.
+
+```sql
+-- Prisma Database Comments Generator v1.0.1
+
+-- customers comments
+COMMENT ON TABLE "customers" IS 'Customer';
+COMMENT ON COLUMN "customers"."customer_id" IS 'Customer ID';
+COMMENT ON COLUMN "customers"."name" IS 'Customer Name';
+COMMENT ON COLUMN "customers"."email" IS 'e-mail';
+
+-- products comments
+COMMENT ON TABLE "products" IS 'Product';
+COMMENT ON COLUMN "products"."product_id" IS 'Product ID';
+COMMENT ON COLUMN "products"."name" IS 'Product Name';
+COMMENT ON COLUMN "products"."type" IS 'Product Type';
+COMMENT ON COLUMN "products"."description" IS 'Product Description';
+COMMENT ON COLUMN "products"."price" IS 'Price';
+
+-- sales comments
+COMMENT ON COLUMN "sales"."sale_id" IS 'Sale ID';
+COMMENT ON COLUMN "sales"."customer_id" IS 'Customer ID';
+COMMENT ON COLUMN "sales"."product_id" IS 'Product ID';
+COMMENT ON COLUMN "sales"."quantity" IS 'Quantity';
+COMMENT ON COLUMN "sales"."total_price" IS 'Total Price';
+```
+
+## Options
+
+### targets
+
+You can select the target with `targets`.
+The default is both `table` and `column`. (`targets = ["table", "column"]`)
+
+For example, the following will only create comments on columns.
+
+```prisma
+generator comments {
+  provider = "prisma-db-comments-generator"
+  targets  = ["column"]
+}
+```
+
+### ignorePattern
+
+Specify the model to be excluded from making comments as a regular expression with `ignorePattern`.  
+The name specified here is the name in the database. Therefore, if `@@map` is specified, it will be the name in `@@map`.
+
+For example, the following is a model with `_view` as a suffix that is excluded.
+
+```prisma
+generator comments {
+  provider      = "prisma-db-comments-generator"
+  ignorePattern = "_view$"
+}
+```
+
+### includeEnumInFeildComment
+
+If `includeEnumInFeildComment` is set to true, information about the enum is appended to the column comment.  
+Default is `false`.
+
+```prisma
+generator comments {
+  provider                  = "prisma-db-comments-generator"
+  includeEnumInFeildComment = true
+}
+```
+
+If `includeEnumInFeildComment` is set to `true` with the following definition,
+
+```prisma
+enum ProductType {
+  BOOK
+  TOY
+  FASHION
+
+  @@map("enum_product_type")
+}
+
+/// Product
+model Product {
+  /// Product Type
+  type ProductType
+
+  // others...
+}
+```
+
+The following comment is generated.
+
+```sql
+COMMENT ON COLUMN "products"."type" IS E'Product Type\nenum: enum_product_type(BOOK, TOY, FASHION)';
+```
+
+## Supported Databases
+
+- PostgreSQL
+
+Other databases may be available, but the above is the only one checked.
+
+## License
+
+MIT
+
+## Author
+
+[onozaty](https://github.com/onozaty)