[英]How to define a multi-field index with Entity Framework Core 2.1
I am working on an ASP.Net Core 2.1 API and I use Entity Framework Core 2.1.我正在研究 ASP.Net Core 2.1 API,我使用 Entity Framework Core 2.1。 I am using migrations to manage changes to the database.
我正在使用迁移来管理对数据库的更改。 My backing data store is an instance of Azure SQL Server.
我的后备数据存储是 Azure SQL Server 的一个实例。
I need to add a multi-field non-clustered index to one of my tables but I am having difficulty finding a concise reference on how to do this in my google searches.我需要将多字段非聚集索引添加到我的一个表中,但我很难在我的 google 搜索中找到有关如何执行此操作的简明参考。
I tried using the [Index()] data annotation in the POCO class but it was not recognized.我尝试在 POCO 类中使用 [Index()] 数据注释,但无法识别。 So, I assume I have to do this in the OnModelCreating method of my DbContext class, but I have not found an example of how to do that for a multi-field non-clustered index.
因此,我假设我必须在 DbContext 类的 OnModelCreating 方法中执行此操作,但我还没有找到有关如何为多字段非聚集索引执行此操作的示例。
Here is an example entity class这是一个示例实体类
public class H1Record : EntityBase
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public long Id { get; set; }
[ForeignKey("ShippingServicesFileId")]
public ShippingServicesFile ShippingServicesFile { get; set; }
[Required]
public int ShippingServicesFileId { get; set; }
[Column(TypeName = "varchar(20)")]
public string BatchId { get; set; }
[Column(TypeName = "varchar(34)")]
[MaxLength(34)]
public string ElectronicFileNumber { get; set; }
[Column(TypeName = "varchar(1)")]
[MaxLength(1)]
public string ElectronicFileType { get; set; }
[Column(TypeName = "varchar(8)")]
[MaxLength(8)]
public string DateOfMailing { get; set; }
[Column(TypeName = "varchar(6)")]
[MaxLength(6)]
public string TimeOfMailing { get; set; }
public DateTime MailingDateTime { get; set; }
[Column(TypeName = "varchar(1)")]
[MaxLength(1)]
public string EntryFacilityType { get; set; }
[Column(TypeName = "varchar(5)")]
[MaxLength(5)]
public string EntryFacilityZipCode { get; set; }
[Column(TypeName = "varchar(4)")]
[MaxLength(4)]
public string EntryFacilityZipPlus4 { get; set; }
[Column(TypeName = "varchar(2)")]
[MaxLength(2)]
public string DirectEntryOriginCountryCode { get; set; }
[Column(TypeName = "varchar(3)")]
[MaxLength(3)]
public string ShipmentFeeCode { get; set; }
[Column(TypeName = "varchar(6)")]
[MaxLength(6)]
public string ExtraFeeForShipment { get; set; }
[Column(TypeName = "varchar(2)")]
[MaxLength(2)]
public string ContainerizationIndicator { get; set; }
[Column(TypeName = "varchar(3)")]
[MaxLength(3)]
public string UspsElectronicFileVersionNumber { get; set; }
[Column(TypeName = "varchar(12)")]
[MaxLength(12)]
public string TransactionId { get; set; }
[Column(TypeName = "varchar(8)")]
[MaxLength(8)]
public string SoftwareVendorProductVersionNumber { get; set; }
[Column(TypeName = "varchar(9)")]
[MaxLength(9)]
public string FileRecordCount { get; set; }
[Column(TypeName = "varchar(9)")]
[MaxLength(9)]
public string MailerId { get; set; }
public ICollection<D1Record> D1Records { get; set; } = new List<D1Record>();
public ICollection<C1Record> C1Records { get; set; } = new List<C1Record>();
}
And here is the entitybase class这是实体基类
public class EntityBase
{
public DateTime CreatedDate { get; set; }
public DateTime LastModifiedDate { get; set; }
public int CreatedByUserId { get; set; }
public int LastModifiedByUserId { get; set; }
public bool DeleteFlag { get; set; }
}
I want to create a non-clustered index for ShippingServicesFileId and DeleteFlag in the OnModelCreating method of my DbContext do that it gets picked up when I run add-migration in my Package Manager Console.我想在我的 DbContext 的 OnModelCreating 方法中为 ShippingServicesFileId 和 DeleteFlag 创建一个非聚集索引,当我在我的包管理器控制台中运行 add-migration 时,它会被拾取。
Any ideas?有任何想法吗?
You cannot create an index on more than one column with data annotations so you have to use Fluent API (in OnModelCreating):您不能在具有数据注释的多个列上创建索引,因此您必须使用 Fluent API(在 OnModelCreating 中):
modeBuilder.Entity<ENTITYCLASS>().HasIndex(x => new {x.PROPERTY1, x.PROPERTY2, ...})
to create a non-clustered index.创建非聚集索引。 Use .IsUnique() to create a unique one.
使用 .IsUnique() 创建一个唯一的。 Use .ForSqlServerIsClustered() if you want a clustered index on a SQL Server.
如果您想在 SQL Server 上使用聚集索引,请使用 .ForSqlServerIsClustered()。 Optionally you can give it another name with .HasName("...").
您可以选择使用 .HasName("...") 为其指定另一个名称。
You can pass in the columns as a string array during a migration if that's your preferred method.如果这是您的首选方法,您可以在迁移期间将列作为字符串数组传入。 Eg
例如
migrationBuilder.CreateIndex("IX_H1Record", "H1Record",new string[] { "ShippingServicesFileId", "DeleteFlag"}, "dbo");
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