Generazione di codice in LINQ to SQL

È possibile generare codice per rappresentare un database usando il Object Relational Designer o lo strumento da riga di comando SQLMetal. In entrambi i casi, si verifica la generazione di codice end-to-end in tre fasi:

  1. L'estrattore DBML estrae le informazioni sullo schema dal database e le riassembla in un file DBML in formato XML.

  2. Il file DBML viene analizzato dal validator DBML per la ricerca di errori.

  3. Se non sono presenti errori di convalida, il file viene passato al generatore di codice.

Per altre informazioni, vedere SqlMetal.exe (strumento per la generazione del codice). Gli sviluppatori Visual Studio possono anche usare il Object Relational Designer per generare codice. Vedere LINQ to SQL Tools in Visual Studio.

Estrattore DBML

L'estrattore DBML è un LINQ to SQL componente che accetta i metadati del database come input e produce un file DBML come output.

Generatore di codice

Il generatore di codice è un componente che converte i file LINQ to SQL DBML in Visual Basic, C# o file di mapping XML.

File di definizione di XML Schema

Il file di mapping DBML deve essere convalidato in base alla seguente definizione dello schema come file XSD.

È necessario distinguere questo file di definizione dello schema dal file di definizione dello schema usato per convalidare un file di mapping esterno. Per altre informazioni, vedere Mapping esterno.

Nota

Visual Studio gli utenti troveranno anche questo file XSD nella finestra di dialogo XML Schema come "DbmlSchema.xsd". Per usare correttamente il file XSD per la convalida di un file DBML, vedere Procedura: Convalidare file DBML ed esterni di mapping.

<?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>  

File DBML di esempio

Il codice seguente è un estratto dal file DBML creato dal database di esempio Northwind. È possibile generare l'intero file usando SQLMetal con l'opzione /xml. Per altre informazioni, vedere SqlMetal.exe (strumento per la generazione del codice).

<?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>  

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