System.Data.Tests.DataSetTest2.Merge_ByDataSet C# (CSharp) Метод

        public void Merge_ByDataSet()
        {
            //create source dataset
            var ds = new DataSet();
            DataTable dt = DataProvider.CreateParentDataTable();
            dt.TableName = "Table1";
            ds.Tables.Add(dt.Copy());
            dt.TableName = "Table2";
            //add primary key
            dt.PrimaryKey = new DataColumn[] { dt.Columns[0] };
            ds.Tables.Add(dt.Copy());

            //create target dataset (copy of source dataset)
            DataSet dsTarget = ds.Copy();
            int iTable1RowsCount = dsTarget.Tables["Table1"].Rows.Count;

            //Source - add another table, don't exists on the target dataset
            ds.Tables.Add(new DataTable("SomeTable"));
            ds.Tables["SomeTable"].Columns.Add("Id");
            ds.Tables["SomeTable"].Rows.Add(new object[] { 777 });

            //Target - add another table, don't exists on the source dataset
            dsTarget.Tables.Add(new DataTable("SmallTable"));
            dsTarget.Tables["SmallTable"].Columns.Add("Id");
            dsTarget.Tables["SmallTable"].Rows.Add(new object[] { 777 });

            //update existing row
            ds.Tables["Table2"].Select("ParentId=1")[0][1] = "OldValue1";
            //add new row
            object[] arrAddedRow = new object[] { 99, "NewValue1", "NewValue2", new DateTime(0), 0.5, true };
            ds.Tables["Table2"].Rows.Add(arrAddedRow);
            //delete existing rows
            foreach (DataRow dr in ds.Tables["Table2"].Select("ParentId=2"))
            {
                dr.Delete();
            }

            // Merge - changed values
            dsTarget.Merge(ds);
            Assert.Equal("OldValue1", dsTarget.Tables["Table2"].Select("ParentId=1")[0][1]);

            // Merge - added values
            Assert.Equal(arrAddedRow, dsTarget.Tables["Table2"].Select("ParentId=99")[0].ItemArray);

            // Merge - deleted row
            Assert.Equal(0, dsTarget.Tables["Table2"].Select("ParentId=2").Length);

            //Table1 rows count should be double (no primary key)
            // Merge - Unchanged table 1
            Assert.Equal(iTable1RowsCount * 2, dsTarget.Tables["Table1"].Rows.Count);

            //SmallTable rows count should be the same
            // Merge - Unchanged table 2
            Assert.Equal(1, dsTarget.Tables["SmallTable"].Rows.Count);

            //SomeTable - new table
            // Merge - new table
            Assert.Equal(true, dsTarget.Tables["SomeTable"] != null);
        }