SQL to C# Classes: EF Core, POCO & Record Guide

Migrating a database schema to a .NET application means writing C# classes that mirror your SQL tables. Doing this manually for dozens of tables is slow and error-prone. This guide shows how to convert SQL CREATE TABLE statements to C# classes — covering EF Core entities, POCOs, and records.

Three C# Output Formats

Depending on your project, you'll want different class styles:

1. Entity Framework Core Entities

Full EF Core entities with data annotations for ORM mapping:

[Table("products")]
public sealed class Products
{
    [Key]
    public int Id { get; set; }

    [Required]
    [MaxLength(200)]
    public string Name { get; set; }

    [Column(TypeName = "decimal(10,2)")]
    public decimal Price { get; set; }

    public string? Description { get; set; }

    [Required]
    public bool IsActive { get; set; }
}C#

2. POCO Classes

Plain classes without ORM attributes — good for DTOs and clean architecture:

public sealed class Products
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    public string? Description { get; set; }
    public bool IsActive { get; set; }
}C#

3. Records (Immutable)

C# records for read-only data transfer:

public sealed record Products(
    int Id,
    string Name,
    decimal Price,
    string? Description,
    bool IsActive
);C#

SQL to C# Type Mapping

Getting the type mapping right is critical. Here's the complete reference:

Data Annotations Reference

EF Core uses these attributes to configure the database mapping:

[Table("table_name")]       // Maps to specific table
[Key]                       // Primary key
[Required]                  // NOT NULL constraint
[MaxLength(200)]            // VARCHAR/NVARCHAR length
[Column(TypeName = "...")]  // Custom column type
[DatabaseGenerated(...)]    // Auto-increment/computedC#

Reverse: C# to SQL

Polymorpher's converter also works in reverse — paste C# classes and get CREATE TABLE statements back. This is useful for:

• Generating database migration scripts from code
• Sharing schema definitions with DBA teams
• Creating documentation for your database structure