System.Data.OracleClient.OracleCommandBuilder，如何生成UpdateCommand

private IDbCommand BuildUpdateCommand(DataTableMapping mappings, DataRow dataRow) 
{ 
      IDbCommand command1 = this.InitializeCommand(this.UpdateCommand); 
      StringBuilder builder1 = this.GetStringBuilder(); 
      int num1 = 0; 
      string text1 = " SET "; 
      builder1.Append("UPDATE "); 
      builder1.Append(this.QuotedBaseTableName); 
      int num2 = this._dbSchemaRows.Length; 
      for (int num3 = 0; num3 < num2; num3++) 
      { 
            DBSchemaRow row1 = this._dbSchemaRows[num3]; 
            if (((row1 != null) && (row1.BaseColumnName.Length != 0)) && this.IncludeInUpdateSet(row1)) 
            { 
                  object obj1 = null; 
                  string text2 = this._sourceColumnNames[num3]; 
                  if ((mappings != null) && (dataRow != null)) 
                  { 
                        DataColumn column1 = this.GetDataColumn(text2, mappings, dataRow); 
                        if ((column1 == null) || (row1.IsReadOnly && column1.ReadOnly)) 
                        { 
                              goto Label_013D; 
                        } 
                        obj1 = this.GetColumnValue(dataRow, column1, DataRowVersion.Current); 
                        if (this.IsNotBehavior(CommandBuilderBehavior.UpdateSetSameValue)) 
                        { 
                              object obj2 = this.GetColumnValue(dataRow, column1, DataRowVersion.Original); 
                              if ((obj2 == obj1) || ((obj2 != null) && obj2.Equals(obj1))) 
                              { 
                                    goto Label_013D; 
                              } 
                        } 
                  } 
                  builder1.Append(text1); 
                  text1 = ", "; 
                  builder1.Append(this.QuotedColumn(row1.BaseColumnName)); 
                  builder1.Append(" = "); 
                  builder1.Append(this.CreateParameterForValue(command1, text2, DataRowVersion.Current, num1, obj1, row1)); 
                  num1++; 
            } 
      Label_013D:; 
      } 
      bool flag1 = 0 == num1; 
      num1 = this.BuildWhereClause(mappings, dataRow, builder1, command1, num1, true); 
      command1.CommandText = builder1.ToString(); 
      OracleCommandBuilder.RemoveExtraParameters(command1, num1); 
      this.UpdateCommand = command1; 
      if (!flag1) 
      { 
            return command1; 
      } 
      return null; 
}