gormcol

Type-safe GORM column descriptors and model generation utilities.

Library

Define struct-like variables mapping Go field names to table.column pairs:

var PsAccess = struct {
    IDProfile           gormcol.Field
    IDAuthorizationRole gormcol.Field
}{
    IDProfile:           gormcol.Field{Table: "ps_access", Column: "id_profile"},
    IDAuthorizationRole: gormcol.Field{Table: "ps_access", Column: "id_authorization_role"},
}

Use the three accessor functions to extract column and table names without string literals:

gormcol.Column(PsAccess.IDAuthorizationRole)      // "id_authorization_role"
gormcol.ColumnOnTable(PsAccess.IDAuthorizationRole) // "ps_access.id_authorization_role"
gormcol.TableField(PsAccess.IDAuthorizationRole)   // "ps_access"

CLI

The cmd/ directory contains a standalone tool that generates GORM model files with column descriptors.

Install

go install git.ma-al.com/goc_marek/gormcol/cmd@latest

Usage

gormcol-gen --dsn <connection-string> [options]

Flag	Default	Description
`--dsn`	(required)	MySQL/MariaDB DSN, e.g. `user:pass@tcp(localhost:3306)/dbname`
`--filter`	`(ps_\|b2b_).*`	Regex matching table names to generate
`--out`	`./app/model/dbmodel`	Output directory for generated files
`--pkg`	`dbmodel`	Go package name for generated files

Example

./gormcol-gen --dsn "user:pass@tcp(localhost:3306)/mydb" --filter "ps_.*" --out ./internal/model --pkg model

This connects to the database, generates a .go model file for each matching table, and appends <Model>Cols variables with typed gormcol.Field descriptors to each file.

Using generated models

After generation, each model file contains a struct and a Cols variable:

// model/product.go
type Product struct {
    ID    uint   `gorm:"column:id_product;primaryKey"`
    Name  string `gorm:"column:name"`
    Price float32 `gorm:"column:price;type:decimal(20,6)"`
}

var ProductCols = struct {
    ID    Field
    Name  Field
    Price Field
}{
    ID:    Field{Table: "ps_product", Column: "id_product"},
    Name:  Field{Table: "ps_product", Column: "name"},
    Price: Field{Table: "ps_product", Column: "price"},
}

GORM queries with type-safe columns

Use ColumnOnTable for table-qualified column references in GORM clauses:

import "git.ma-al.com/goc_marek/gormcol"

// Where clauses
db.Where(
    gormcol.ColumnOnTable(model.ProductCols.Price) + " > ?",
    100.0,
).Find(&products)

// Order
db.Order(gormcol.ColumnOnTable(model.ProductCols.Name) + " ASC").Find(&products)

// Joins
db.Joins("JOIN ps_category ON " +
    gormcol.ColumnOnTable(model.ProductCols.ID) + " = ps_category.id_product",
).Find(&products)

Unqualified column names

Use Column when the table is already scoped:

db.Select(gormcol.Column(model.ProductCols.Name)).Find(&products)

// Raw queries
db.Raw("SELECT " + gormcol.Column(model.ProductCols.Name) + " FROM ps_product").Scan(&names)

Table name

Use TableField to get the table name from a column descriptor:

table := gormcol.TableField(model.ProductCols.ID) // "ps_product"

Dependencies

gorm.io/gorm
gorm.io/gen
gorm.io/driver/mysql

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