Entity Base Classes

Namespace: ZhonTai.Admin.Core.Entities

Zhongtai Admin provides a complete entity base class system that implements common functionality such as primary keys, audit fields, soft delete, multi-tenancy, data permissions, and optimistic locking through interface composition and inheritance chains.

Use Cases

• Choose the appropriate base class when creating database table entities
• Avoid repeating common fields in every entity
• Automatically benefit from global filters (soft delete, tenant isolation, data permissions)

Inheritance Hierarchy

Primary Key Entity Chain (with audit + soft delete)

Entity<TKey>                        Primary key Id (Snowflake)
  └── EntityAdd<TKey>               + Create audit fields
        └── EntityUpdate<TKey>      + Update audit fields
              └── EntityDelete<TKey> + Soft delete field
                    └── EntityBase    Complete base class (recommended)

No-PK Entity Chain (audit only)

IEntityAdd                          Create audit interface
  └── EntityAddNoId                 + Create audit fields
        └── EntityUpdateNoId        + Update audit fields

EntityBase<TKey> Derived Classes

EntityBase<TKey>
  ├── EntityTenant<TKey>            + Tenant isolation
  │     └── EntityTenantWithData<TKey> + Data permissions
  ├── EntityData<TKey>              + Data permissions (no tenant)
  ├── EntityVersion<TKey>           + Optimistic locking
  └── EntityMember<TKey>            + Member (with soft delete + time audit)
        └── EntityMemberWithTenant<TKey> + Tenant isolation

Composable Interfaces

Interface	Fields	Description
IEntity<TKey>	Id	Primary key
IEntityAdd	CreatedUserId/Name/RealName/Time	Create audit
IEntityUpdate	ModifiedUserId/Name/RealName/Time	Update audit
IDelete	IsDeleted	Soft delete
ITenant	TenantId	Multi-tenancy
IMember	MemberId	Member
IData	OwnerId/OwnerOrgId/OwnerOrgName	Data permissions
IVersion	Version	Optimistic locking
IChilds<T>	List<T> Childs	Tree children

Base Class Fields

Entity<TKey>

Base entity with Snowflake ID primary key.

public class Entity<TKey> : IEntity<TKey>
{
    [Snowflake] // Auto-generated Snowflake ID
    public virtual TKey Id { get; set; }
}

Non-generic shortcut: Entity (i.e. Entity<long>)

TIP

Typically use the non-generic shortcut class Entity (i.e. Entity<long>, primary key is long). No need to specify a generic parameter.

EntityAdd<TKey>

Adds create audit fields to Entity:

Field	Type	Description
CreatedUserId	long?	Creator user ID
CreatedUserName	string	Creator username
CreatedUserRealName	string	Creator real name
CreatedTime	DateTime?	Created time ([ServerTime] auto-assigned)

Non-generic shortcut: EntityAdd (i.e. EntityAdd<long>)

EntityUpdate<TKey>

Adds update audit fields to EntityAdd:

Field	Type	Description
ModifiedUserId	long?	Modifier user ID
ModifiedUserName	string	Modifier username
ModifiedUserRealName	string	Modifier real name
ModifiedTime	DateTime?	Modified time (CanInsert=false, CanUpdate=true)

Non-generic shortcut: EntityUpdate (i.e. EntityUpdate<long>)

EntityDelete<TKey>

Adds soft delete to EntityUpdate:

Field	Type	Default	Description
IsDeleted	bool	false	Soft delete flag

Non-generic shortcut: EntityDelete (i.e. EntityDelete<long>)

TIP

Entities inheriting IDelete automatically convert delete operations to IsDeleted=true updates. FreeSql global filters automatically filter deleted records.

EntityBase<TKey>

Complete base class inheriting EntityDelete (includes primary key + audit + soft delete). The most commonly used base class.

Non-generic shortcut: EntityBase (i.e. EntityBase<long>)

EntityAddNoId

No-primary-key create audit entity. Implements IEntityAdd only. Suitable for tables without independent primary key (e.g. association tables, log tables).

Field	Type	Description
CreatedUserId	long?	Creator user ID
CreatedUserName	string	Creator username
CreatedUserRealName	string	Creator real name
CreatedTime	DateTime?	Created time ([ServerTime] auto-assigned)

EntityUpdateNoId

No-primary-key update audit entity. Inherits EntityAddNoId, implements IEntityUpdate.

Field	Type	Description
ModifiedUserId	long?	Modifier user ID
ModifiedUserName	string	Modifier username
ModifiedUserRealName	string	Modifier real name
ModifiedTime	DateTime?	Modified time (CanInsert=false, CanUpdate=true)

EntityTenant<TKey>

Multi-tenant entity. Inherits EntityBase, implements ITenant. When multi-tenancy is enabled, queries are automatically filtered by tenant — each tenant can only access its own data.

Field	Type	Description
TenantId	long?	Tenant ID (cannot be modified after creation)

Non-generic shortcut: EntityTenant (i.e. EntityTenant<long>)

EntityTenantWithData<TKey>

Multi-tenant + data permission entity. Inherits EntityTenant, implements IData. Supports both tenant isolation and data permission filtering.

Field	Type	Description
TenantId	long?	Tenant ID (from EntityTenant)
OwnerId	long?	Owner ID
OwnerOrgId	long?	Owner department ID
OwnerOrgName	string	Owner department name

Non-generic shortcut: EntityTenantWithData (i.e. EntityTenantWithData<long>)

EntityData<TKey>

Data permission entity. Inherits EntityBase, implements IData. Supports data permission filtering (without tenant isolation). Suitable for scenarios that need data permissions but not multi-tenancy.

Field	Type	Description
OwnerId	long?	Owner ID
OwnerOrgId	long?	Owner department ID
OwnerOrgName	string	Owner department name

Non-generic shortcut: EntityData (i.e. EntityData<long>)

EntityVersion<TKey>

Optimistic locking entity. Inherits EntityBase, implements IVersion. Updates automatically check the version number. A concurrency exception is thrown if versions don't match. Suitable for high-concurrency update scenarios.

Field	Type	Description
Version	long	Data version ([Column(IsVersion = true)])

Non-generic shortcut: EntityVersion (i.e. EntityVersion<long>)

EntityMember<TKey>

Member entity. Inherits Entity, implements IMember and IDelete. Unlike EntityBase, it does not include full audit fields — only MemberId, time audit, and soft delete.

Field	Type	Description
Id	TKey	Primary key (Snowflake ID)
MemberId	long?	Member ID
CreatedTime	DateTime?	Created time ([ServerTime])
ModifiedTime	DateTime?	Modified time (CanInsert=false, CanUpdate=true)
IsDeleted	bool	Soft delete flag (default false)

Non-generic shortcut: EntityMember (i.e. EntityMember<long>)

EntityMemberWithTenant<TKey>

Member + tenant entity. Inherits EntityMember, implements ITenant.

Field	Type	Description
MemberId	long?	Member ID (from EntityMember)
TenantId	long?	Tenant ID (cannot be modified after creation)

Non-generic shortcut: EntityMemberWithTenant (i.e. EntityMemberWithTenant<long>)

Examples

Basic Entity (with audit + soft delete)

The most commonly used entity. Inherits EntityBase, includes primary key, create/update audit, and soft delete.

using FreeSql.DataAnnotations;
using ZhonTai.Admin.Core.Entities;

public class ArticleEntity : EntityBase
{
    [Description("Title")]
    [MaxLength(200)]
    public string Title { get; set; }

    [Description("Content")]
    [Column(StringLength = -1)]
    public string Content { get; set; }

    public bool Enabled { get; set; }
}

Multi-tenant Entity

Use when tenant data isolation is needed. Inherits EntityTenant.

public class ConfigEntity : EntityTenant
{
    [Description("Key")]
    [MaxLength(100)]
    public string Key { get; set; }

    [Description("Value")]
    [Column(StringLength = -1)]
    public string Value { get; set; }
}

Multi-tenant + Data Permission Entity

Use when both tenant isolation and data permission filtering are needed. Inherits EntityTenantWithData.

public class OrderEntity : EntityTenantWithData
{
    public string OrderNo { get; set; }
    public decimal Amount { get; set; }
}

This is equivalent to having all these fields: Id, audit fields, IsDeleted, TenantId, OwnerId, OwnerOrgId, OwnerOrgName.

Data Permission Entity (no tenant)

Use when data permissions are needed without multi-tenancy. Inherits EntityData.

public class ProjectEntity : EntityData
{
    public string Name { get; set; }
    public long? OwnerId { get; set; }               // Owner
    public long? OwnerOrgId { get; set; }            // Department
}

Optimistic Locking Entity

Use in high-concurrency update scenarios to prevent conflicts. Inherits EntityVersion.

public class SettingEntity : EntityVersion
{
    [Description("Key")]
    [MaxLength(100)]
    public string Key { get; set; }

    [Description("Value")]
    [Column(StringLength = -1)]
    public string Value { get; set; }
}

Member Entity

For frontend member data. Inherits EntityMember, includes MemberId, time audit, and soft delete.

public class AddressEntity : EntityMember
{
    [Description("Receiver")]
    [MaxLength(50)]
    public string Receiver { get; set; }

    [Description("Phone")]
    [MaxLength(20)]
    public string Phone { get; set; }

    [Description("Address")]
    [MaxLength(200)]
    public string Address { get; set; }
}

Member + Tenant Entity

Use when member data needs tenant isolation. Inherits EntityMemberWithTenant.

public class CartEntity : EntityMemberWithTenant
{
    public long ProductId { get; set; }
    public int Quantity { get; set; }
}

No-PK Entity (association table)

For tables without independent primary key. Inherits EntityUpdateNoId.

public class ArticleTagEntity : EntityUpdateNoId
{
    public long ArticleId { get; set; }
    public long TagId { get; set; }
}

Tree Entity

For tree structures. Inherits EntityBase and implements IChilds<T>.

public class CategoryEntity : EntityBase, IChilds<CategoryEntity>
{
    [Description("Parent ID")]
    public long ParentId { get; set; }

    [Description("Name")]
    [MaxLength(50)]
    public string Name { get; set; }

    public List<CategoryEntity> Childs { get; set; }
}

Tree + Multi-tenant Entity

public class CategoryEntity : EntityTenant, IChilds<CategoryEntity>
{
    public long ParentId { get; set; }
    public string Name { get; set; }
    public List<CategoryEntity> Childs { get; set; }
}

Primary Key Only Entity

When only a Snowflake ID is needed without audit and soft delete. Inherits Entity.

public class DictEntity : Entity
{
    public string Name { get; set; }
    public string Value { get; set; }
}

Auto-assignment Attributes

Attribute	Description
[Snowflake]	Auto-generate Snowflake ID for primary key
[ServerTime]	Auto-assign server time on insert
[ServerTime(CanInsert=false, CanUpdate=true)]	Auto-assign server time on update only
[Column(IsVersion = true)]	Optimistic locking version field