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Geração de código em LINQ para SQL

  • Artigo

Você pode gerar código para representar um banco de dados usando Designer Relacional de Objetos ou a ferramenta de linha de comando SQLMetal. Em ambos os casos, a geração de código ponta a ponta ocorre em três estágios:

  1. O Extrator de DBML extrai informações do esquema do banco de dados e reúne novamente as informações em um arquivo DBML com formato XML.

  2. O arquivo DBML é verificado pelo Validador de DBML em busca de erros.

  3. Se nenhum erro de validação aparecer, o arquivo será passado para o Gerador de Código.

Para obter mais informações, consulte SqlMetal.exe (ferramenta de geração de código). Desenvolvedores que utilizam o Visual Studio também podem usar o Object Relational Designer para mapear as hierarquias de herança. Confira Ferramentas do LINQ to SQL no Visual Studio.

Extrator de DBML

O Extrator de DBML é um componente de LINQ to SQL que usa metadados do banco de dados como entrada e gera um arquivo DBML como saída.

Gerador de Código

O Gerador de Código é um componente de LINQ to SQL que converte arquivos DBML em Virtual Basic, C# ou arquivos de mapeamento XML.

Arquivo de Definição de Esquema XML

O arquivo DBML deve ser válido em relação à seguinte definição de esquema como um arquivo XSD.

Diferencie este arquivo de definição do esquema do arquivo de definição do esquema que é usado para validar um arquivo de mapeamento externo. Para saber mais, confira Mapeamento externo.

Observação

Os usuários do Visual Studio também encontrarão esse arquivo XSD na caixa de diálogo Esquemas XML como “DbmlSchema.xsd”. Para usar o arquivo XSD corretamente para validar um arquivo DBML, consulte Como validar arquivos de mapeamento externo e DBML.

<?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>

Arquivo DBML de exemplo

O código a seguir é um trecho do arquivo DBML criado do banco de dados de exemplo Northwind. Você pode gerar o arquivo inteiro usando o SQLMetal com a opção /xml. Para obter mais informações, consulte SqlMetal.exe (ferramenta de geração de código).

<?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>

Confira também