c# - 如何让 Entityframework Core 设置正确的参数数据类型

Question

我有一个定义了此属性的用户模型:

[Column("custnmbr", TypeName = "char(15)")]
[StringLength(15)]
public string Custnmbr { get; set; }

我在查询中引用了这个:

.FromSqlInterpolated($"SELECT * FROM [cp].[GetEcommerceItemsView] WHERE [CustomerNumber] = {user.Custnmbr}")

但是当Entityframework Core Interpolates我的参数，它将数据类型设置为 @p0 AS nvarchar(4000) .这会导致 CONVERT_IMPLICIT在我的查询计划中:

Type conversion in expression (CONVERT_IMPLICIT(nchar(15),[C].[CUSTNMBR],0)=[@p0]) may affect "SeekPlan" in query plan choice

我的问题是:我是否应该为此担心，如果是，我该如何解决？

Answer 1

您可以尝试切换到 FromSqlRaw和创造 SqlParameter具有显式类型。像这样的东西:

var p1 = new SqlParameter("@Custnmbr", SqlDbType.Char, 15);
p1.Value = user.Custnmbr;
(...)
.FromSqlRaw($"SELECT * FROM [cp].[GetEcommerceItemsView] WHERE [CustomerNumber] = @Custnmbr", p1);