EF：从 C# 将表值参数传递给用户定义的函数

Question

我在 SQL Server 中有一个用户定义的函数，它接受 TVP（表值参数）作为参数。在 EF 中，如何从 C# 调用这样的函数？

我尝试使用ObjectContext.CreateQuery<>的方法，但出现以下错误：

函数“QueryByParam”的参数“param”无效。参数只能是可以转换为 Edm 标量类型的类型。

还尝试了方法ObjectContext.ExecuteStoreQuery<> 并得到了同样的错误。无论如何它都不会返回IQueryable。

示例代码

[DbFunction(nameof(SampleDbContext), "QueryByParam")]
public IQueryable<SecurityQueryRow> QueryByParam(IEnumerable<ProfileType> profiles, bool isActive = false)
{
    DataTable dataTable = ....
    ObjectParameter profilesParam = new ObjectParameter("profileTypeIds", dataTable);

    ObjectParameter isActiveParam = new ObjectParameter("isActive ", isActive);

    return ((IObjectContextAdapter)this).ObjectContext.CreateQuery<SecurityQueryRow>(
            string.Format("[{0}].[{1}](@profileTypeIds, @isActive)", GetType().Name, "QueryByParam"),
            profilesParam,
            isActiveParam);
}

要求是我们需要一个 IQueryable 返回，而不是消费的结果。

Answer 1

您可以使用 Raw Sql en EF Core，EF6 中的类似方法，但您无法获得 IQueryable。以下两个示例。

实体框架核心

将其用作列表过滤器的 SQL 类型：

CREATE TYPE [dbo].[Table1Type] AS TABLE(
    [Id] [int] NULL,
    [Name] [nchar](10) NULL
)

SQL UDF：

CREATE FUNCTION [dbo].[Func1] 
(   
    @Ids Table1Type readonly
)
RETURNS TABLE 
AS
RETURN
(
    SELECT * from Table1 where id in (select Id from @Ids)
)

EF 上下文：

public class MyContext : DbContext
{
    public DbSet<Table1> Table1 { get; set; }
}

DTO 匹配 sql 类型（为简单起见也与表相同）：

public class Table1
{
    public int Id { get; set; }
    public string Name { get; set; }
}

示例：

static void Main(string[] args)
{
    using (var context = new MyContext())
    {
        // Declare de Structure filter param
        var dt = new DataTable();

        DataTable table = new DataTable();
        table.Columns.Add(new DataColumn("Id", typeof(int)));
        table.Columns.Add(new DataColumn("Name", typeof(string)));
        DataRow row = table.NewRow();
        row["Id"] = 1;
        row["Name"] = "Item";
        table.Rows.Add(row);
        var param = new SqlParameter("@Ids", table) { TypeName = "dbo.Table1Type", SqlDbType = SqlDbType.Structured };

        IQueryable<Table1> query = context.Table1.FromSqlRaw("SELECT * FROM dbo.func1(@Ids)", param);
        var result = query.ToList();
    }
}

实体框架 6

您无法获得 IQueryable，但您可以链接到生成的 IEnumerable。

static void Main(string[] args)
{
    using (var context = new MyContext())
    {
        context.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);

        // Declare de Structure filter param
        var dt = new DataTable();

        DataTable table = new DataTable();
        table.Columns.Add(new DataColumn("Id", typeof(int)));
        table.Columns.Add(new DataColumn("Name", typeof(string)));
        DataRow row = table.NewRow();
        row["Id"] = 1;
        row["Name"] = "Item";
        table.Rows.Add(row);
        var param = new SqlParameter("@Ids", table) { TypeName = "dbo.Table1Type", SqlDbType = SqlDbType.Structured };

        var query = context.Table1.SqlQuery("SELECT * FROM dbo.func1(@Ids)", param);

        var result = query.ToList();
    }
}

Answer 2

AdventureWorks示例数据库有一个表值函数dbo.ufnGetContactInformation，它的返回类型也可以表示为另一种复杂类型

[ComplexType]
public class ContactInformation
{
    public int PersonID { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string JobTitle { get; set; }

    public string BusinessEntityType { get; set; }
}

那么ufnGetContactInformation函数可以映射为：

// Defines table-valued function, which must return IQueryable<T>.
[Function(FunctionType.TableValuedFunction, nameof(ufnGetContactInformation), Schema = dbo)]
public IQueryable<ContactInformation> ufnGetContactInformation(
    [Parameter(DbType = "int", Name = "PersonID")]int? personId)
{
    ObjectParameter personIdParameter = personId.HasValue
        ? new ObjectParameter("PersonID", personId)
        : new ObjectParameter("PersonID", typeof(int));

    return this.ObjectContext().CreateQuery<ContactInformation>(
        $"[{nameof(this.ufnGetContactInformation)}](@{nameof(personId)})", personIdParameter);
}

它的返回类型应该是 IQueryable，以便它可以在 LINQ to Entities 中组合。并且可以调用：

[TestMethod]
public void CallTableValuedFunction()
{
    using (AdventureWorks database = new AdventureWorks())
    {
        IQueryable<ContactInformation> employees = database.ufnGetContactInformation(1).Take(2);
        Assert.IsNotNull(employees.Single());
    }
}

上述 ufnGetContactInformation 调用和 Take 调用将被转换为单个 SQL 查询：

exec sp_executesql N'SELECT TOP (2) 
    [top].[C1] AS [C1], 
    [top].[PersonID] AS [PersonID], 
    [top].[FirstName] AS [FirstName], 
    [top].[LastName] AS [LastName], 
    [top].[JobTitle] AS [JobTitle], 
    [top].[BusinessEntityType] AS [BusinessEntityType]
    FROM ( SELECT TOP (2) 
        [Extent1].[PersonID] AS [PersonID], 
        [Extent1].[FirstName] AS [FirstName], 
        [Extent1].[LastName] AS [LastName], 
        [Extent1].[JobTitle] AS [JobTitle], 
        [Extent1].[BusinessEntityType] AS [BusinessEntityType], 
        1 AS [C1]
        FROM [dbo].[ufnGetContactInformation](@PersonID) AS [Extent1]
    )  AS [top]',N'@PersonID int',@PersonID=1