LINQ to SQL 中的代码生成

项目
04/07/2023

可以使用对象关系设计器或 SQLMetal 命令行工具生成代码来表示数据库。在任一情况下，端到端代码生成都分成三个阶段：

DBML 提取器从数据库中提取架构信息，然后将信息重新组合到 XML 格式的 DBML 文件中。
DBML 验证程序对 DBML 文件进行扫描，检查是否有错误。
如果未显示验证错误，文件将传递到代码生成器。

有关详细信息，请参阅 SqlMetal.exe（代码生成工具）。使用 Visual Studio 的开发人员还可以使用对象关系设计器生成代码。请参阅 Visual Studio 中的 LINQ to SQL 工具。

DBML 提取器

DBML 提取器是一个 LINQ to SQL 组件，它采用数据库元数据作为输入，生成 DBML 文件作为输出。

代码生成器

代码生成器是一个 LINQ to SQL 组件，可将 DBML 文件转换为 Visual Basic、C# 或 XML 映射文件。

XML 架构定义文件

DBML 文件必须对下面的 XSD 架构定义文件有效。

请将此架构定义文件与用于验证外部映射文件的架构定义文件区分开来。有关详细信息，请参阅外部映射。

备注

Visual Studio 用户还会发现此 XSD 文件在“XML 架构”对话框中名为“DbmlSchema.xsd”。若要正确使用 XSD 文件验证 DBML 文件，请参阅如何：验证 DBML 和外部映射文件。

<?xml version="1.0" encoding="utf-16"?>  
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://schemas.microsoft.com/linqtosql/dbml/2007" xmlns="http://schemas.microsoft.com/linqtosql/dbml/2007"  
elementFormDefault="qualified" >  
  <xs:element name="Database" type="Database" />  
  <xs:complexType name="Database">  
    <xs:sequence>  
      <xs:element name="Connection" type="Connection" minOccurs="0" maxOccurs="1" />  
      <xs:element name="Table" type="Table" minOccurs="0" maxOccurs="unbounded" />  
      <xs:element name="Function" type="Function" minOccurs="0" maxOccurs="unbounded" />  
    </xs:sequence>  
    <xs:attribute name="Name" type="xs:string" use="optional" />  
    <xs:attribute name="EntityNamespace" type="xs:string" use="optional" />  
    <xs:attribute name="ContextNamespace" type="xs:string" use="optional" />  
    <xs:attribute name="Class" type="xs:string" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="ClassModifier" use="optional" />  
    <xs:attribute name="BaseType" type="xs:string" use="optional" />  
    <xs:attribute name="Provider" type="xs:string" use="optional" />  
    <xs:attribute name="ExternalMapping" type="xs:boolean" use="optional" />  
    <xs:attribute name="Serialization" type="SerializationMode" use="optional" />  
    <xs:attribute name="EntityBase" type="xs:string" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Table">  
    <xs:all>  
      <xs:element name="Type" type="Type" minOccurs="1" maxOccurs="1" />  
      <xs:element name="InsertFunction" type="TableFunction" minOccurs="0" maxOccurs="1" />  
      <xs:element name="UpdateFunction" type="TableFunction" minOccurs="0" maxOccurs="1" />  
      <xs:element name="DeleteFunction" type="TableFunction" minOccurs="0" maxOccurs="1" />  
    </xs:all>  
    <xs:attribute name="Name" type="xs:string" use="required" />  
    <xs:attribute name="Member" type="xs:string" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="MemberModifier" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Type">  
    <xs:sequence>  
      <xs:choice minOccurs="0" maxOccurs="unbounded">  
        <xs:element name="Column" type="Column" minOccurs="0" maxOccurs="unbounded" />  
        <xs:element name="Association" type="Association" minOccurs="0" maxOccurs="unbounded" />  
      </xs:choice>  
      <xs:element name="Type" type="Type" minOccurs="0" maxOccurs="unbounded" />  
    </xs:sequence>  
    <xs:attribute name="IdRef" type="xs:IDREF" use="optional" />  
    <xs:attribute name="Id" type="xs:ID" use="optional" />  
    <xs:attribute name="Name" type="xs:string" use="optional" />  
    <xs:attribute name="InheritanceCode" type="xs:string" use="optional" />  
    <xs:attribute name="IsInheritanceDefault" type="xs:boolean" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="ClassModifier" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Column">  
    <xs:attribute name="Name" type="xs:string" use="optional" />  
    <xs:attribute name="Member" type="xs:string" use="optional" />  
    <xs:attribute name="Storage" type="xs:string" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="MemberModifier" use="optional" />  
    <xs:attribute name="Type" type="xs:string" use="required" />  
    <xs:attribute name="DbType" type="xs:string" use="optional" />  
    <xs:attribute name="IsReadOnly" type="xs:boolean" use="optional" />  
    <xs:attribute name="IsPrimaryKey" type="xs:boolean" use="optional" />  
    <xs:attribute name="IsDbGenerated" type="xs:boolean" use="optional" />  
    <xs:attribute name="CanBeNull" type="xs:boolean" use="optional" />  
    <xs:attribute name="UpdateCheck" type="UpdateCheck" use="optional" />  
    <xs:attribute name="IsDiscriminator" type="xs:boolean" use="optional" />  
    <xs:attribute name="Expression" type="xs:string" use="optional" />  
    <xs:attribute name="IsVersion" type="xs:boolean" use="optional" />  
    <xs:attribute name="IsDelayLoaded" type="xs:boolean" use="optional" />  
    <xs:attribute name="AutoSync" type="AutoSync" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Association">  
    <xs:attribute name="Name" type="xs:string" use="required" />  
    <xs:attribute name="Member" type="xs:string" use="required" />  
    <xs:attribute name="Storage" type="xs:string" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="MemberModifier" use="optional" />  
    <xs:attribute name="Type" type="xs:string" use="required" />  
    <xs:attribute name="ThisKey" type="xs:string" use="optional" />  
    <xs:attribute name="OtherKey" type="xs:string" use="optional" />  
    <xs:attribute name="IsForeignKey" type="xs:boolean" use="optional" />  
    <xs:attribute name="Cardinality" type="Cardinality" use="optional" />  
    <xs:attribute name="DeleteRule" type="xs:string" use="optional" />  
    <xs:attribute name="DeleteOnNull" type="xs:boolean" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Function">  
    <xs:sequence>  
      <xs:element name="Parameter" type="Parameter" minOccurs="0" maxOccurs="unbounded" />  
      <xs:choice>  
        <xs:element name="ElementType" type="Type" minOccurs="0" maxOccurs="unbounded" />  
        <xs:element name="Return" type="Return" minOccurs="0" maxOccurs="1" />  
      </xs:choice>  
    </xs:sequence>  
    <xs:attribute name="Name" type="xs:string" use="required" />  
    <xs:attribute name="Id" type="xs:ID" use="optional" />  
    <xs:attribute name="Method" type="xs:string" use="optional" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
    <xs:attribute name="Modifier" type="MemberModifier" use="optional" />  
    <xs:attribute name="HasMultipleResults" type="xs:boolean" use="optional" />  
    <xs:attribute name="IsComposable" type="xs:boolean" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="TableFunction">  
    <xs:sequence>  
      <xs:element name="Argument" type="TableFunctionParameter" minOccurs="0" maxOccurs="unbounded" />  
      <xs:element name="Return" type="TableFunctionReturn" minOccurs="0" maxOccurs="1" />  
    </xs:sequence>  
    <xs:attribute name="FunctionId" type="xs:IDREF" use="required" />  
    <xs:attribute name="AccessModifier" type="AccessModifier" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Parameter">  
    <xs:attribute name="Name" type="xs:string" use="required" />  
    <xs:attribute name="Parameter" type="xs:string" use="optional" />  
    <xs:attribute name="Type" type="xs:string" use="required" />  
    <xs:attribute name="DbType" type="xs:string" use="optional" />  
    <xs:attribute name="Direction" type="ParameterDirection" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="Return">  
    <xs:attribute name="Type" type="xs:string" use="required" />  
    <xs:attribute name="DbType" type="xs:string" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="TableFunctionParameter">  
    <xs:attribute name="Parameter" type="xs:string" use="required" />  
    <xs:attribute name="Member" type="xs:string" use="required" />  
    <xs:attribute name="Version" type="Version" use="optional" />  
  </xs:complexType>  
  <xs:complexType name="TableFunctionReturn">  
    <xs:attribute name="Member" type="xs:string" use="required" />  
  </xs:complexType>  
  <xs:complexType name="Connection">  
    <xs:attribute name="Provider" type="xs:string" use="required" />  
    <xs:attribute name="Mode" type="ConnectionMode" use="optional" />  
    <xs:attribute name="ConnectionString" type="xs:string" use="optional" />  
    <xs:attribute name="SettingsObjectName" type="xs:string" use="optional" />  
    <xs:attribute name="SettingsPropertyName" type="xs:string" use="optional" />  
  </xs:complexType>  
  <xs:simpleType name="ConnectionMode">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="ConnectionString" />  
      <xs:enumeration value="AppSettings" />  
      <xs:enumeration value="WebSettings" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="AccessModifier">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Public" />  
      <xs:enumeration value="Internal" />  
      <xs:enumeration value="Protected" />  
      <xs:enumeration value="ProtectedInternal" />  
      <xs:enumeration value="Private" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="UpdateCheck">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Always" />  
      <xs:enumeration value="Never" />  
      <xs:enumeration value="WhenChanged" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="SerializationMode">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="None" />  
      <xs:enumeration value="Unidirectional" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="ParameterDirection">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="In" />  
      <xs:enumeration value="Out" />  
      <xs:enumeration value="InOut" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="Version">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Current" />  
      <xs:enumeration value="Original" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="AutoSync">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Never" />  
      <xs:enumeration value="OnInsert" />  
      <xs:enumeration value="OnUpdate" />  
      <xs:enumeration value="Always" />  
      <xs:enumeration value="Default" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="ClassModifier">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Sealed" />  
      <xs:enumeration value="Abstract" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="MemberModifier">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="Virtual" />  
      <xs:enumeration value="Override" />  
      <xs:enumeration value="New" />  
      <xs:enumeration value="NewVirtual" />  
    </xs:restriction>  
  </xs:simpleType>  
  <xs:simpleType name="Cardinality">  
    <xs:restriction base="xs:string">  
      <xs:enumeration value="One" />  
      <xs:enumeration value="Many" />  
    </xs:restriction>  
  </xs:simpleType>  
</xs:schema>

DBML 文件示例

下面的代码摘自从 Northwind 示例数据库创建的 DBML 文件。可以使用 SQLMetal 通过 /xml 选项生成整个文件。有关详细信息，请参阅 SqlMetal.exe（代码生成工具）。

<?xml version="1.0" encoding="utf-16"?>  
<Database Name="northwnd" Class="Northwnd" xmlns="http://schemas.microsoft.com/dsltools/DLinqML">  
  
  <Table Name="Customers">  
    <Type Name="Customer">  
      <Column Name="CustomerID" Type="System.String" DbType="NChar(5) NOT NULL" IsPrimaryKey="True" CanBeNull="False" />  
      <Column Name="CompanyName" Type="System.String" DbType="NVarChar(40) NOT NULL" CanBeNull="False" />  
      <Column Name="ContactName" Type="System.String" DbType="NVarChar(30)" CanBeNull="True" />  
      <Column Name="ContactTitle" Type="System.String" DbType="NVarChar(30)" CanBeNull="True" />  
      <Column Name="Address" Type="System.String" DbType="NVarChar(60)" CanBeNull="True" />  
      <Column Name="City" Type="System.String" DbType="NVarChar(15)" CanBeNull="True" />  
      <Column Name="Region" Type="System.String" DbType="NVarChar(15)" CanBeNull="True" />  
      <Column Name="PostalCode" Type="System.String" DbType="NVarChar(10)" CanBeNull="True" />  
      <Column Name="Country" Type="System.String" DbType="NVarChar(15)" CanBeNull="True" />  
      <Column Name="Phone" Type="System.String" DbType="NVarChar(24)" CanBeNull="True" />  
      <Column Name="Fax" Type="System.String" DbType="NVarChar(24)" CanBeNull="True" />  
      <Association Name="FK_CustomerCustomerDemo_Customers" Member="CustomerCustomerDemos" ThisKey="CustomerID" OtherKey="CustomerID" OtherTable="CustomerCustomerDemo" DeleteRule="NO ACTION" />  
      <Association Name="FK_Orders_Customers" Member="Orders" ThisKey="CustomerID" OtherKey="CustomerID" OtherTable="Orders" DeleteRule="NO ACTION" />  
    </Type>  
  </Table>  
</Database>

LINQ to SQL 中的代码生成

DBML 提取器

代码生成器

XML 架构定义文件

DBML 文件示例

请参阅

其他资源