c# - Pass table value type to SQL Server stored procedure via Entity Framework

Question

I created a user-defined table type in SQL Server:

CREATE TYPE dbo.TestType AS TABLE 
(
    ColumnA int,
    ColumnB nvarchar(500)
)

And I'm using a stored procedure to insert records into the database:

create procedure [dbo].[sp_Test_CustomType]
   @testing TestType READONLY
as
    insert into [dbo].[myTable]
        select ColumnA, ColumnB 
        from @testing

And I would like to use EF to execute this stored procedure, but here's the problem: how can I pass a user defined table to the stored procedure?

I tried adding the stored procedure to the model, but I'm unable to find the desired stored procedure in the updated context.

What I'm trying to do is to execute a bulk insert to a table, here's the method that I'm currently using:

List<items> itemToInsertToDB = //fetchItems;

foreach(items i in itemToInsertToDB)
{
     context.sp_InsertToTable(i.ColumnA, i.ColumnB)
}

Currently, I use a foreach loop to loop through the list to insert item to DB, but if the list have a lot of items, then there will be a performance issue, so, I'm thinking of passing a list to the stored procedure and do the insert inside.

So how to solve this problem? or are there any better ways to do this?

Answer 1

Lets say you want to send a table with a single column of GUIDs.

First we need to create a structure using SqlMetaData which represents the schema of the table (columns).

The below code demonstrates one column named "Id" of the GUID is the SQL stored procedure parameter table type

var tableSchema = new List<SqlMetaData>(1)
{
  new SqlMetaData("Id", SqlDbType.UniqueIdentifier)
}.ToArray();

Next you create a list of records that match the schema using SqlDataRecord.

The below code demonstrates how to add the items inside a list using the above created schema. Create a new SqlDataRecord for each of the items in the list. Replace SetGuid with the corresponding type and Replace Guid.NewGuid() as the corresponding value. Repeat new SqlDataRecord for each item and add them to a List

var tableRow = new SqlDataRecord(tableSchema);
tableRow.SetGuid(0, Guid.NewGuid());
var table = new List<SqlDataRecord>(1)
{
  tableRow
};

Then create the SqlParameter:

var parameter = new SqlParameter();
parameter.SqlDbType = SqlDbType.Structured;
parameter.ParameterName = "@UserIds"; //@UserIds is the stored procedure parameter name
parameter.TypeName = "{Your stored procedure type name}"
parameter.Value = table;

var parameters = new SqlParameter[1]
{
  parameter
};

Then simply call the stored procedure by using the Database.SqlQuery.

IEnumerable<ReturnType> result;
using (var myContext = new DbContext())
{
  result = myContext.Database.SqlQuery<User>("GetUsers @UserIds", parameters)
    .ToList();         // calls the stored procedure
    // ToListAsync();  // Async
{

In SQL Server, create your User-Defined Table Type (I suffix them with TTV, Table Typed Value):

CREATE TYPE [dbo].[UniqueidentifiersTTV] AS TABLE(
  [Id] [uniqueidentifier] NOT NULL
)
GO

Then specify the type as a parameter (don't forget, Table Type Values have to be readonly!):

CREATE PROCEDURE [dbo].[GetUsers] (
  @UserIds [UniqueidentifiersTTV] READONLY
) AS
BEGIN
  SET NOCOUNT ON

  SELECT u.* -- Just an example :P
  FROM [dbo].[Users] u
  INNER JOIN @UserIds ids On u.Id = ids.Id
END