go-gorm-model: Скилл для генерации моделей Go

--- name: go-gorm-model description: Generate Go GORM models following Go modular architecture conventions. Use when creating or updating persistence models in internal/modules/<module>/model/, including table mapping, nullable pointer types, index tags, PostgreSQL-specific types, and timestamps. Always use this skill when asked to create a model, add a GORM struct, map a database table, or generate model files. --- # Go GORM Model Generate GORM persistence models in `internal/modules/<module>/model/`. ## Pattern Model files must follow this location and naming: - Path: `internal/modules/<module>/model/<entity>_model.go` - Package: `model` - Struct name: `<Entity>Model` - TableName method: `func (*<Entity>Model) TableName() string { return "<table_name>" }` ## File Structure Use this order: 1. `package model` 2. Imports (`"time"` only — add others only when strictly required) 3. Struct definition with doc comment 4. `TableName()` method with doc comment ## Base Template ```go package model import "time" // EntityModel represents an entity in the database. type EntityModel struct { ID uint64 `gorm:"primarykey"` Name string CreatedAt time.Time UpdatedAt time.Time } // TableName returns the table name for the entity model. func (*EntityModel) TableName() string { return "entities" } ``` ## Conventions ### IDs and Primary Keys - Use `uint64` for the `ID` primary key field, always tagged `gorm:"primarykey"`. - Foreign key fields (references to another table's PK) also use `uint64` when NOT NULL, or `*uint64` when nullable. ### Time Fields - Use `time.Time` for `TIMESTAMPTZ` columns (`CreatedAt`, `UpdatedAt`, etc.). - No explicit column tag needed — GORM maps `CreatedAt` → `created_at` by convention. ### Nullable Fields Use **Go pointer types** for nullable columns. Never use `database/sql` types (`sql.NullString`, `sql.NullInt32`, etc.) — those are not used in this codebase. | SQL nullable type | Go type | |---|---| | `TEXT` / `VARCHAR` nullable | `*string` | | `BIGINT` nullable (value) | `*int64` | | `BIGINT` nullable (FK) | `*uint64` | | `BOOLEAN` nullable | `*bool` | | `TIMESTAMPTZ` nullable | `*time.Time` | Examples from this codebase: ```go Description *string // nullable TEXT PromotionalPrice *int64 // nullable BIGINT value CategoryID *uint64 // nullable BIGINT FK SceneContext *string // nullable TEXT ``` ### Column Tags Do NOT add `gorm:"column:..."` tags. GORM automatically maps Go field names to snake_case column names (`ProductID` → `product_id`, `CreatedAt` → `created_at`, etc.). Only add tags when there is a specific GORM feature to declare. Add tags only for: - `gorm:"primarykey"` — primary key - `gorm:"uniqueIndex"` / `gorm:"uniqueIndex:name"` — unique constraints - `gorm:"index"` — regular indexes - `gorm:"type:jsonb"` — PostgreSQL JSONB columns - `gorm:"default:'value'"` — column-level defaults - `gorm:"->;column:name"` — computed/read-only virtual columns ### Index and Constraint Tags Declare indexes inline on the field: ```go Slug string `gorm:"uniqueIndex"` ProductID uint64 `gorm:"index"` // Named composite unique index (both fields must share the same name) CollectionID uint64 `gorm:"uniqueIndex:idx_collection_product"` ProductID uint64 `gorm:"uniqueIndex:idx_collection_product"` ``` ### PostgreSQL-Specific Types - `JSONB` → `[]byte` with `gorm:"type:jsonb"` - `default` values → `gorm:"default:'value'"` ```go Attributes []byte `gorm:"type:jsonb"` PrimaryColor string `gorm:"default:'#1d4ed8'"` ``` ### Value Types vs FK Types BIGINT is not always `uint64`. Distinguish by semantics: - Primary key: `uint64` with `gorm:"primarykey"` - Foreign key NOT NULL: `uint64` - Foreign key nullable: `*uint64` - Numeric value (price, weight, size, quantity): `int64` / `*int64` - Small integer (sort order, display order): `int` - Boolean: `bool` ## Generation Steps 1. Identify module and entity. 2. Read the migration SQL file and confirm the exact table name and column definitions. 3. Create `internal/modules/<module>/model/<entity>_model.go`. 4. Map each SQL column to the correct Go field name and type. 5. Use pointer types for nullable columns. 6. Add GORM tags only where needed (index, uniqueIndex, type, default). 7. Add doc comment to the struct and to `TableName()`. 8. Verify struct field order matches the column order in the migration (for readability). ## Type Mapping Guide | SQL Type | NOT NULL | Nullable | |---|---|---| | `BIGSERIAL PRIMARY KEY` | `uint64` + `gorm:"primarykey"` | — | | `BIGINT` FK | `uint64` | `*uint64` | | `BIGINT` value | `int64` | `*int64` | | `INT` | `int` | `*int` | | `VARCHAR` / `TEXT` | `string` | `*string` | | `BOOLEAN` | `bool` | `*bool` | | `TIMESTAMPTZ` | `time.Time` | `*time.Time` | | `JSONB` | `[]byte` + `gorm:"type:jsonb"` | — | ## Example: Simple Model ```go package model import "time" // CategoryModel represents a category in the database. type CategoryModel struct { ID uint64 `gorm:"primarykey"` Name string `gorm:"uniqueIndex"` Slug string `gorm:"uniqueIndex"` ShowInMenu bool CreatedAt time.Time UpdatedAt time.Time } // TableName returns the table name for the category model. func (*CategoryModel) TableName() string { return "categories" } ``` ## Example: Model with Nullable Fields and JSONB ```go package model import "time" // ProductModel represents a product in the database. type ProductModel struct { ID uint64 `gorm:"primarykey"` Title string Description string Price int64 PromotionalPrice *int64 SKU string `gorm:"uniqueIndex"` Status string WeightGrams *int64 WidthCm *int64 LengthCm *int64 HeightCm *int64 StockQuantity int64 CategoryID *uint64 Attributes []byte `gorm:"type:jsonb"` CreatedAt time.Time UpdatedAt time.Time } // TableName returns the table name for the product model. func (*ProductModel) TableName() string { return "products" } ``` ## Example: Join Table (Composite Unique Index) ```go package model import "time" // CollectionProductModel represents the many-to-many relationship // between collections and products. type CollectionProductModel struct { ID uint64 `gorm:"primarykey"` CollectionID uint64 `gorm:"uniqueIndex:idx_collection_product"` ProductID uint64 `gorm:"uniqueIndex:idx_collection_product"` CreatedAt time.Time } // TableName returns the table name for the collection product model. func (*CollectionProductModel) TableName() string { return "collection_products" } ``` ## Example: Model with Default Values ```go package model import "time" // ProfileModel represents the business profile in the database. type ProfileModel struct { ID uint64 `gorm:"primarykey"` BusinessName string WhatsAppPhone string LogoPath string LogoMimeType string PrimaryColor string `gorm:"default:'#1d4ed8'"` AccentColor string `gorm:"default:'#16a34a'"` CreatedAt time.Time UpdatedAt time.Time } // TableName returns the table name for the profile model. func (*ProfileModel) TableName() string { return "profiles" } ``` ## Critical Rules - Models are persistence only — business logic belongs in use cases. - Do not expose GORM models directly in HTTP DTO responses. - Keep field names and types aligned with SQL migrations. - Use Go pointer types (`*string`, `*int64`, `*uint64`) for nullable columns — never `database/sql` types. - Do NOT add `gorm:"column:..."` tags unless GORM convention cannot handle the mapping. - Never use `json` tags on GORM models. - Use module-local model package only (`internal/modules/<module>/model`). - Always add doc comments on the struct and `TableName()` method. - Do not change existing column or table names without a corresponding migration update. ## Checklist - [ ] File at `internal/modules/<module>/model/<entity>_model.go` - [ ] Struct named `<Entity>Model` with doc comment - [ ] `ID uint64` with `gorm:"primarykey"` - [ ] Nullable columns use pointer types (`*string`, `*int64`, `*uint64`) - [ ] No `database/sql` import or nullable SQL types - [ ] No explicit `gorm:"column:..."` tags unless required - [ ] Index/constraint tags present where migration defines them (`uniqueIndex`, `index`) - [ ] PostgreSQL-specific columns tagged (`type:jsonb`, `default:...`) - [ ] `TableName()` with doc comment returns exact SQL table name - [ ] No `json` tags