`Adapter.Update (DataTable);` 方法更新 table 数据源的所有行，还是仅更新那些已修改的行？

Question

Adapter.Update (DataTable); 方法更新 table 数据源的所有行，还是仅更新那些已修改的行？

逻辑：
- 连接到数据库；
- 我们对 tables;
行进行抽样 - 用户进行更改；
- 保存。方法Save()。

我使用代码来处理数据库：

public DataTable CreateCmds()
        {
            table_2 = new DataTable();
            try
            {
                string connectionString = @"Data Source=.\SQLEXPRESS1;Initial Catalog=Prb;Integrated Security=True";              

                string queryString = "SELECT * FROM tbl_01_Groups";
                // string connectString = "Data Source=.\SQLEXPRESS;Initial Catalog=LSTU_Schedule_autumn20172018;" + "Integrated Security=true;";

                using (SqlConnection connection = new SqlConnection(connectionString))
                {
                    adapter = new SqlDataAdapter();
                    adapter.SelectCommand = new SqlCommand(queryString, connection);
                    SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

                    connection.Open();

                    adapter.Fill(table_2);
                }

            }
            catch (Exception ex)
            {

                string s = ex.Message;
                string t = ex.StackTrace;
                // throw;
            }

            return table_2;
        }

        public void Save()
        {
            string connectionString = @"Data Source=.\SQLEXPRESS1;Initial Catalog=Prb;Integrated Security=True";

            string queryString = "SELECT * FROM tbl_01_Groups";

            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                adapter = new SqlDataAdapter();
                adapter.SelectCommand = new SqlCommand(queryString, connection);
                SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

                connection.Open();

                adapter.Update(table_2);
            }
        }

Update_1
我在网络上没有找到答案，这个问题的解决方法。
问题是代码效率提升引起的
我以为执行表达式adapter.Update(DataTable)时，代码会遍历数据源table.
的所有行如果是这种情况，那么可能有更有效的方法来对代码进行采样以仅更新更改的行。

Answer 1

DataTable.Rows[index].RowState 指的是数据行的状态。

ADO.NET 将检查状态，仅在状态更改时更新。

请参考https://docs.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqldataadapter?view=netframework-4.7.2#remarks

The update is performed on a by-row basis. For every inserted, modified, and deleted row, the Update method determines the type of change that has been performed on it

`Adapter.Update (DataTable);` 方法更新 table 数据源的所有行，还是仅更新那些已修改的行？

The `Adapter.Update (DataTable);` method updates all rows of the table data source or only those rows that have been modified?

c#

ado.net