asp.net-mvc-5 – EntityFramework 6 – 处理用户定义的属性

>我添加了MetaAttributeList以允许一个列表应用于多个MetaAttributes.在此模型中,布尔值将表示为是/否列表选项.
>问题的模型将要求搜索值检查(3个)表中的一个,并且提前知道适用的MetaAttribute
>问题的模型,默认情况下使用EF Code First,会出现多个CASCADE路径的问题,这需要使用FluentApi(不是很大,但可能不方便跟踪)
>这种方法(可选地？)要求在代码而不是数据库中处理有效ListOption条目的强制执行
>显示不同类型的值不需要任何额外的工作来正确呈现
>管理界面需要检查MetaAttribute.ListOption以确定是否显示TextBox或ListItem(如果ListItemOptions为Yes / No,则可能是一个复选框)
>您可能希望为ToolGroups添加另一个表,以缩小呈现给用户的MetaAttributes

注意：由于未指定EF方法和语言,因此我使用了EF Code First和VB.Net. IMO迁移和更容易过渡到EF7是足以使用Code First的原因.我更喜欢VB.Net的可读性,但如果需要(或使用this转换器),我很乐意改为C#.

Imports System.ComponentModel.DataAnnotations
Namespace Models
    'I didn't bother specifying string lengths with <StringLength(#)>
    Public Class HireTool
        Public Property Id As Integer
        '... other properties

        'Navigation Properties
        Public Overridable Property HireToolMetaAttributes As ICollection(Of HireToolMetaAttribute)
    End Class
    Public Class MetaAttribute
        Public Enum MetaAttributeTypeEnum
            Text = 1
            ListItem = 2
        End Enum
        Public Property Id As Integer
        Public Property Code As String
        Public Property Label As String
        Public Property Type As MetaAttributeTypeEnum
        Public Property Required As Boolean
        Public Property Position As Integer
        'Navigation Properties
        Public Overridable Property List As MetaAttributeList
    End Class
    Public Class MetaAttributeList
        Public Property ID As Integer
        Public Property Name As String
        'Navigation Properties
        <Required>
        Public Property ListOptions As ICollection(Of MetaAttributeListOption)
    End Class
    Public Class MetaAttributeListOption
        Public Property Id As Integer
        Public Property OptionLabel As String
    End Class
    Public Class HireToolMetaAttribute
        Public Property Id As Integer
        <Schema.Index> <StringLength(1000)>
        Public Property Value As String
        <Required>
        Public Overridable Property HireTool As HireTool
        <Required>
        Public Overridable Property MetaAttribute As MetaAttribute
    End Class
End Namespace

编辑：这是生成的SQL：

CREATE TABLE [dbo].[MetaAttributeLists] (
    [ID]   INT            IDENTITY (1,1) NOT NULL,[Name] NVARCHAR (MAX) NULL,CONSTRAINT [PK_dbo.MetaAttributeLists] PRIMARY KEY CLUSTERED ([ID] ASC)
);
CREATE TABLE [dbo].[HireTools] (
    [Id] INT IDENTITY (1,CONSTRAINT [PK_dbo.HireTools] PRIMARY KEY CLUSTERED ([Id] ASC)
);
CREATE TABLE [dbo].[MetaAttributeListOptions] (
    [Id]                   INT            IDENTITY (1,[OptionLabel]          NVARCHAR (MAX) NULL,[MetaAttributeList_ID] INT            NULL,CONSTRAINT [PK_dbo.MetaAttributeListOptions] PRIMARY KEY CLUSTERED ([Id] ASC),CONSTRAINT [FK_dbo.MetaAttributeListOptions_dbo.MetaAttributeLists_MetaAttributeList_ID] FOREIGN KEY ([MetaAttributeList_ID]) REFERENCES [dbo].[MetaAttributeLists] ([ID])
);
CREATE TABLE [dbo].[MetaAttributes] (
    [Id]       INT            IDENTITY (1,[Code]     NVARCHAR (MAX) NULL,[Label]    NVARCHAR (MAX) NULL,[Type]     INT            NOT NULL,[Required] BIT            NOT NULL,[Position] INT            NOT NULL,[List_ID]  INT            NULL,CONSTRAINT [PK_dbo.MetaAttributes] PRIMARY KEY CLUSTERED ([Id] ASC),CONSTRAINT [FK_dbo.MetaAttributes_dbo.MetaAttributeLists_List_ID] FOREIGN KEY ([List_ID]) REFERENCES [dbo].[MetaAttributeLists] ([ID])
);
CREATE TABLE [dbo].[HireToolMetaAttributes] (
    [Id]               INT             IDENTITY (1,[Value]            NVARCHAR (1000) NULL,[HireTool_Id]      INT             NOT NULL,[MetaAttribute_Id] INT             NOT NULL,CONSTRAINT [PK_dbo.HireToolMetaAttributes] PRIMARY KEY CLUSTERED ([Id] ASC),CONSTRAINT [FK_dbo.HireToolMetaAttributes_dbo.HireTools_HireTool_Id] FOREIGN KEY ([HireTool_Id]) REFERENCES [dbo].[HireTools] ([Id]) ON DELETE CASCADE,CONSTRAINT [FK_dbo.HireToolMetaAttributes_dbo.MetaAttributes_MetaAttribute_Id] FOREIGN KEY ([MetaAttribute_Id]) REFERENCES [dbo].[MetaAttributes] ([Id]) ON DELETE CASCADE
);
GO
CREATE NONCLUSTERED INDEX [IX_Value]
    ON [dbo].[HireToolMetaAttributes]([Value] ASC);
GO
CREATE NONCLUSTERED INDEX [IX_HireTool_Id]
    ON [dbo].[HireToolMetaAttributes]([HireTool_Id] ASC);
GO
CREATE NONCLUSTERED INDEX [IX_MetaAttribute_Id]
    ON [dbo].[HireToolMetaAttributes]([MetaAttribute_Id] ASC);
GO
CREATE NONCLUSTERED INDEX [IX_MetaAttributeList_ID]
    ON [dbo].[MetaAttributeListOptions]([MetaAttributeList_ID] ASC);
GO
CREATE NONCLUSTERED INDEX [IX_List_ID]
    ON [dbo].[MetaAttributes]([List_ID] ASC);