Avoiding the 2100 parameter limit in LINQ to SQL

Question

In a project I am currently working on, I need to access 2 databases in LINQ in the following manner:

1. I get a list of all trip numbers between a specified d

Answer 1

Not sure whether this will help, but I had a similar issue for a one-off query I was writing in LinqPad and ended up defining and using a temporary table like this.

[Table(Name="#TmpTable1")]
public class TmpRecord
{
    [Column(DbType="Int", IsPrimaryKey=true, UpdateCheck=UpdateCheck.Never)]
    public int? Value { get; set; }         
}

public Table<TmpRecord> TmpRecords
{
    get { return base.GetTable<TmpRecord>(); }
}

public void DropTable<T>()
{
    ExecuteCommand( "DROP TABLE " + Mapping.GetTable(typeof(T)).TableName  );
}

public void CreateTable<T>()
{
   ExecuteCommand(
    typeof(DataContext)
    .Assembly
    .GetType("System.Data.Linq.SqlClient.SqlBuilder")
    .InvokeMember("GetCreateTableCommand", 
      BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.InvokeMethod
     , null, null, new[] { Mapping.GetTable(typeof(T)) } ) as string
    );      
}

Usage is something like

void Main()
{
    List<int> ids = .... 

    this.Connection.Open();
    // Note, if the connection is not opened here, the temporary table  
    // will be created but then dropped immediately.

    CreateTable<TmpRecord>();    
    foreach(var id in ids)
        TmpRecords.InsertOnSubmit( new TmpRecord() { Value = id}) ;
    SubmitChanges();

    var list1 = (from r in CustomerTransaction 
        join tt in TmpRecords on r.CustomerID equals tt.Value 
        where ....
        select r).ToList();

     DropTable<TmpRecord>();    
     this.Connection.Close();    

}

In my case the temporary table only had one int column, but you should be able to define whatever column(s) type you want, (as long as you have a primary key).

Answer 2

as LINQ-to-SQL can call stored procs, you could

• have a stored proc that takes an array as a input then puts the values in a temp table to join on
• likewise by taking a string that the stored proc splits

Or upload all the values to a temp table yourself and join on that table.

However maybe you should rethink the problem:

• Sql server can be configured to allow query against tables in other databases (including oracle), if you are allowed this may be an option for you.
• Could you use some replication system to keep a table of trip numbers updated in DB2?

Answer 3

You may split your query or use a temporary table in database2 filled with results from database1.