How to pass dynamic table name in gorm model

When using the GORM ORM library in Go, we typically map models to a fixed database table. However, in certain cases, we may need to dynamically define or change the table name associated with the model. GORM provides a way to dynamically set the table name by implementing the Tabler interface.

Implementing the Tabler Interface

To dynamically change the table name of a model, implement the TableName method of the Tabler interface within the model. This way, every time GORM executes an operation, it calls the TableName method to retrieve the table name.

Here is a simple example:

go
package main

import (
    "gorm.io/gorm"
    "gorm.io/driver/sqlite"
    "fmt"
)

// Define model
 type Product struct {
    gorm.Model
    Code  string
    Price uint
 }

// Implement Tabler interface
 func (Product) TableName() string {
    // Here, you can return different table names based on configuration files, environment variables, or other logic
    return "dynamic_table_name"
 }

func main() {
    // Initialize database connection
    db, err := gorm.Open(sqlite.Open("test.db"), &gorm.Config{})
    if err != nil {
        panic("failed to connect database")
    }

    // Auto-migrate mode
    db.AutoMigrate(&Product{})

    // Create
    db.Create(&Product{Code: "D42", Price: 100})

    // Query
    var product Product
    db.First(&product, 1) // Find product with id 1
    fmt.Println(product.Code, product.Price)

    // At this point, all database operations apply to the `dynamic_table_name` table
}

In this example, for any operation—create, query, update, or delete—the Product model uses dynamic_table_name as the table name. This approach is particularly suitable for applications that need to isolate data based on different customers or multi-tenant environments.

Important Considerations

• When using dynamic table names, ensure that the table name is correctly set before any operation is executed, especially in concurrent environments.
• Managing dynamic table names requires caution to avoid introducing security vulnerabilities, such as SQL injection.
• For complex logic, consider encapsulating the table name determination logic into a separate function or method to make the code clearer and more maintainable.

By using the above method, you can flexibly control the table name of GORM models to adapt to different business requirements.