Updated Readme files

pkg/readers/yaml/README.md

@@ -0,0 +1,159 @@
+# YAML Reader
+
+Reads database schema definitions from YAML files.
+
+## Overview
+
+The YAML Reader parses YAML files that define database schemas in RelSpec's canonical YAML format and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Reads RelSpec's standard YAML schema format
+- Human-readable alternative to JSON format
+- Supports complete schema representation including:
+  - Databases and schemas
+  - Tables, columns, and data types
+  - Constraints (PK, FK, unique, check)
+  - Indexes
+  - Relationships
+  - Views and sequences
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.yaml",
+    }
+
+    reader := yaml.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read YAML schema and convert to GORM models
+relspec --input yaml --in-file schema.yaml --output gorm --out-file models.go
+
+# Convert YAML to PostgreSQL DDL
+relspec --input yaml --in-file database.yaml --output pgsql --out-file schema.sql
+
+# Transform YAML to JSON
+relspec --input yaml --in-file schema.yaml --output json --out-file schema.json
+```
+
+## Example YAML Schema
+
+```yaml
+name: myapp
+database_type: postgresql
+schemas:
+  - name: public
+    tables:
+      - name: users
+        schema: public
+        columns:
+          id:
+            name: id
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            auto_increment: true
+            sequence: 1
+          username:
+            name: username
+            type: varchar
+            length: 50
+            not_null: true
+            sequence: 2
+          email:
+            name: email
+            type: varchar
+            length: 100
+            not_null: true
+            sequence: 3
+        constraints:
+          pk_users:
+            name: pk_users
+            type: PRIMARY KEY
+            columns:
+              - id
+          uq_users_username:
+            name: uq_users_username
+            type: UNIQUE
+            columns:
+              - username
+        indexes:
+          idx_users_email:
+            name: idx_users_email
+            columns:
+              - email
+            unique: false
+            type: btree
+      - name: posts
+        schema: public
+        columns:
+          id:
+            name: id
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            sequence: 1
+          user_id:
+            name: user_id
+            type: bigint
+            not_null: true
+            sequence: 2
+          title:
+            name: title
+            type: varchar
+            length: 200
+            not_null: true
+            sequence: 3
+        constraints:
+          fk_posts_user_id:
+            name: fk_posts_user_id
+            type: FOREIGN KEY
+            columns:
+              - user_id
+            referenced_table: users
+            referenced_schema: public
+            referenced_columns:
+              - id
+            on_delete: CASCADE
+            on_update: NO ACTION
+```
+
+## Schema Structure
+
+The YAML format mirrors RelSpec's internal model structure with human-readable syntax:
+
+- Database level: `name`, `database_type`, `schemas`
+- Schema level: `name`, `tables`, `views`, `sequences`
+- Table level: `name`, `schema`, `columns`, `constraints`, `indexes`, `relationships`
+- Column level: `name`, `type`, `length`, `not_null`, `default`, etc.
+
+## Notes
+
+- YAML format is more human-readable than JSON
+- Ideal for manual editing and version control
+- Comments are supported in YAML
+- Preserves complete schema information
+- Can be used for configuration and documentation