Entity Design

Art Admin uses EF Core as the ORM with MySQL 8.0. Entity classes follow a set of conventions.

Base Classes

EntityBase

public class EntityBase
{
    public long Id { get; set; }
    public DateTime CreatedTime { get; set; }
}

EntityBaseWithUpdate

public class EntityBaseWithUpdate : EntityBase
{
    public DateTime? UpdatedTime { get; set; }
}

Entity Definition Example

[Table("sys_user")]
public class SysUser : EntityBaseWithUpdate
{
    public string Username { get; set; } = string.Empty;
    public string Password { get; set; } = string.Empty;
    public string? Nickname { get; set; }
    public string? Avatar { get; set; }
    public int Status { get; set; }
    public long? RoleId { get; set; }
    public string? TenantId { get; set; }

    [ForeignKey(nameof(RoleId))]
    public SysRole? Role { get; set; }
}

Key Conventions

ID Strategy

• All IDs use long type
• Generated by Snowflake ID algorithm via IdGen.NextId()
• Framework auto-handles frontend precision (see JSON Serialization)

Table Name Mapping

[Table("sys_user")]     // Explicitly specify table name
public class SysUser : EntityBaseWithUpdate { }

Column Naming

EF Core is configured with snake_case naming convention. Property RoleId maps to column role_id.

Navigation Properties

Use [ForeignKey] with nameof() for type-safe navigation:

public long? RoleId { get; set; }

[ForeignKey(nameof(RoleId))]
public SysRole? Role { get; set; }

Important

Database does NOT create foreign key constraints. [ForeignKey] only tells EF Core the relationship for navigation property loading. No actual FK constraint in MySQL.

Query with Navigation

var users = await _db.SysUsers
    .Include(x => x.Role)           // Load role data
    .Where(x => x.Status == 1)
    .Select(x => new UserDto
    {
        Id = x.Id,
        Username = x.Username,
        RoleName = x.Role!.Name     // Access navigation property
    })
    .ToListAsync();

Registering Entities

All entities must be registered in ArtDbContext:

public class ArtDbContext : DbContext
{
    public DbSet<SysUser> SysUsers => Set<SysUser>();
    public DbSet<SysRole> SysRoles => Set<SysRole>();
    public DbSet<SysMenu> SysMenus => Set<SysMenu>();
    // ...
}