如何在c＃中实施此计划以读取所有数据并写入另一个表？

Question

I have two tables in SQL Server:

• Table 1 with columns name , family , address
• Table 2 with columns name , family

And my server properties is this:

• RAM: 64GB
• Intel 24 core xeon

Im the table 1 may be have 30 million, and I want read all data that, and just insert name and family from table 1 to table 2. I'm using Linq-to-SQL, but that is slow, how can I implement that scenario rapidly in C#? Thanks.

Answer 1

You can execute the following query on the server:

 INSERT INTO table2
 SELECT Name, Family
   FROM table1

That will copy all the records from table1 into table2 directly on the SQL Server.

Of course, if you must do it from C#, you can execute the same query using a SQLCommand.

using (SqlConnection connection = new SqlConnection(connectionString))
{
    String query = @"INSERT INTO table2
                       SELECT Name, Family
                         FROM table1";
    SqlCommand command = new SqlCommand(query, connection);
    command.Connection.Open();
    command.ExecuteNonQuery();
}

If you need to do some processing to the data in C# a good option is to use the SqlBulkCopy class but it's going to take a bit more work to set up the operation.

Answer 2

You can using following code:

         // db = DataContext
         var toInsert = from t1 in db.Table1
           where ...
           select new Table2
           {
               name = b.name,
               family = b.family
           };
        db.Table2.InsertAllOnSubmit(toInsert);
        db.SubmitChanges();