Question

我想在Dot Net core 3.1中执行带有输出参数的存储过程。我正在使用lead = Lead.objects.get(id=id) .... ..... if form.is_valid(): item = form.instance item.save() lead.ticket_set.add(item) lead.save()类的<dependency> <groupId>org.apache.flink</groupId> <artifactId>flink-clients_2.11</artifactId> <version>1.9.1</version> </dependency>扩展方法。

C＃代码以获取员工人数。

ExecuteSqlInterpolated

执行后，employeeCount为DatabaseFacade，而string deptName="IT"; int? employeeCount = null; Database.ExecuteSqlInterpolated($"exec dbo.usp_GetEmpCountByDept {deptName}, {employeeCount} out");是返回值。由于某些人要求存储用于重现该问题的proc代码，因此我将proc存储如下：

null

Answer 1

我找到了另一种对我有用的方法

添加Nuget包Microsoft.Data.SqlClient
改用ExecuteSqlRaw方法

下面是代码

    int? employeeCount = null;
    string deptName="IT";

    // Use Microsoft.Data.SqlClient namespace for SqlParameter.Visual studio will suggest  "system.data.sqlclient" which does not work
    var deptNameSQLParam = new Microsoft.Data.SqlClient.SqlParameter("@Dept", deptName);
    var employeeCountSQLParam = new Microsoft.Data.SqlClient.SqlParameter("@EmpCount", SqlDbType.Int) { Direction = ParameterDirection.Output }; 
    Database.ExecuteSqlRaw("exec dbo.usp_GetEmpCountByDept @Dept={0}, @EmpCount={1} out", deptNameSQLParam, employeeCountSQLParam);

     if (employeeCountSQLParam.Value != DBNull.Value)
     {
        employeeCount = (int)employeeCountSQLParam.Value;
     }

Answer 2

ExecuteSqlInterpolated对数据库执行给定的SQL，并返回受影响的行数。

您不能期望通过此方法返回数据。

请参阅此MSDN文档。 https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.relationaldatabasefacadeextensions.executesqlinterpolated?view=efcore-3.1

Answer 3

更改此

string deptName="IT";
int? employeeCount = null;
Database.ExecuteSqlInterpolated($"exec dbo.usp_GetEmpCountByDept {deptName}, {employeeCount} out");

对此（使用.NET 5为我工作，之前不知道）

string deptName="IT";

// make explicit SQL Parameter
var output = new SqlParameter("@EmployeeCount", SqlDbType.Int) { Direction = ParameterDirection.Output };

// use output parameter instead
Database.ExecuteSqlInterpolated($"exec dbo.usp_GetEmpCountByDept {deptName}, {output} out");

// assign output
int? employeeCount = output.Value;

如何在Dot Net Core 3.1中使用FromSqlInterpolated / Database.ExecuteSqlInterpolated执行带有输出参数的存储过程？

3 个答案: