根据数据数组更新数据库表记录

Question

I have an array of objects like this:

[ {User_ID: 1, Source_ID: 1}, {User_ID: 1, Source_ID: 2}]

And my access table design:

AccessID	User_ID	Source_ID
1	1	1
2	1	2
3	2	1
4	2	2

If I want to update the access records for User_ID = 1 to [ {User_ID: 1, Source_ID: 1}, {User_ID: 1, Source_ID: 3} ]

How can I Remove the access record "User_ID = 1, Source_ID = 2" And Insert the access record "User_ID = 1, Source_ID = 3", but keep the "User_ID = 1, Source_ID = 1" record.

Using stored procedure?

What I have so far:

C#:

...Create the DB Command and add parameter "Source_ID"..

foreach (var SourceID in user.SourceAccess)
{
  dBCall1.GetCommand().Parameters["Source_ID"].Value = SourceID;
  dBCall1.ExecuteNonQuery;
}

Stored Procedure:

CREATE PROCEDURE [dbo].[UpdateUserSourceAccess]
    @UserID INT,
    @SourceID INT
AS
IF NOT EXISTS (SELECT 1 FROM [UserSourceAccess] WHERE [User_ID] = @UserID AND Source_ID = @SourceID)
    INSERT INTO UserSourceAccess
    ( UserID, SourceID ) VALUES ( @UserID, @SourceID )
...

Answer 1

The problem with what you are trying to do, is that you need to be able to compare a full list of Source_ID per user, and insert or delete as necessary.

For this to work, you need the procedure to have the full list to compare, so you are best off passing in a Table-Valued Parameter. I usually keep a few standard table-types for this purpose:

CREATE TYPE IdList (Id int PRIMARY KEY);

GO

Then you need to do a partial MERGE : in other words do not MERGE the full table, because then any other users will get all their rows deleted. Instead pre-filter the target table with a CTE. We can then MERGE against the CTE, comparing against the table parameter.

CREATE OR ALTER PROCEDURE [dbo].[UpdateUserSourceAccess]
    @UserID int,
    @SourceIDs dbo.IdList
AS

SET NOCOUNT ON;

WITH t AS (
    SELECT t.AccessID, t.User_ID, t.Source_ID
    FROM YourTable t
    WHERE t.User_ID = @UserID
)
MERGE INTO t
USING @SourceIDs s
  ON s.Id = t.Source_ID
WHEN NOT MATCHED BY SOURCE
  THEN DELETE
WHEN NOT MATCHED BY TARGET
  THEN INSERT (User_ID, Source_ID)
       VALUES (@UserID, s.val)
;

GO

You can call it from C# like this

using(var comm = new SqlCommand("UpdateUserSourceAccess", yourConnection))
{
    var table = new DataTable { Columns = { { "Id", typeof(int) } } };
    foreach (var SourceID in user.SourceAccess)
        table.Rows.Add(SourceID);

    comm.Parameters.Add(new SqlParameter("@SourceIDs", SqlDbType.Structured)
    {
        TypeName = "dbo.IdList",
        Direction = ParameterDirection.Input,
        Value = table
    });
    comm.ExecuteNonQuery;
}