System.Data.Common.DbCommandBuilder.BuildUpdateCommand C# (CSharp) Method

        private DbCommand BuildUpdateCommand(DataTableMapping mappings, DataRow dataRow)
        {
            DbCommand command = InitializeCommand(UpdateCommand);
            StringBuilder builder = new StringBuilder();
            string nextSeparator = Set;
            int parameterCount = 0;

            Debug.Assert(!string.IsNullOrEmpty(_quotedBaseTableName), "no table name");

            builder.Append(Update);
            builder.Append(QuotedBaseTableName);

            // search for the columns in that base table, to build the set clause
            DbSchemaRow[] schemaRows = _dbSchemaRows;
            for (int i = 0; i < schemaRows.Length; ++i)
            {
                DbSchemaRow row = schemaRows[i];

                if ((null == row) || (0 == row.BaseColumnName.Length) || !IncludeInUpdateSet(row))
                    continue;

                object currentValue = null;
                string sourceColumn = _sourceColumnNames[i];

                // If we're building a statement for a specific row, then check the
                // values to see whether the column should be included in the update
                // statement or not
                if ((null != mappings) && (null != dataRow))
                {
                    DataColumn dataColumn = GetDataColumn(sourceColumn, mappings, dataRow);

                    if (null == dataColumn)
                        continue;

                    // Don't bother updating if the column is readonly in both the data
                    // set and the back end.
                    if (row.IsReadOnly && dataColumn.ReadOnly)
                        continue;

                    // Unless specifically directed to do so, we will not automatically update
                    // a column with it's original value, which means that we must determine
                    // whether the value has changed locally, before we send it up.
                    currentValue = GetColumnValue(dataRow, dataColumn, DataRowVersion.Current);

                    if (!SetAllValues)
                    {
                        object originalValue = GetColumnValue(dataRow, dataColumn, DataRowVersion.Original);

                        if ((originalValue == currentValue)
                            || ((null != originalValue) && originalValue.Equals(currentValue)))
                        {
                            continue;
                        }
                    }
                }

                builder.Append(nextSeparator);
                nextSeparator = Comma;

                builder.Append(QuotedColumn(row.BaseColumnName));
                builder.Append(Equal);
                builder.Append(
                    CreateParameterForValue(
                        command,
                        GetBaseParameterName(i),
                        sourceColumn,
                        DataRowVersion.Current,
                        parameterCount,
                        currentValue,
                        row, StatementType.Update, false
                    )
                );
                parameterCount++;
            }

            // It is an error to attempt an update when there's nothing to update;
            bool skipRow = (0 == parameterCount);

            parameterCount = BuildWhereClause(mappings, dataRow, builder, command, parameterCount, true);

            command.CommandText = builder.ToString();

            RemoveExtraParameters(command, parameterCount);
            UpdateCommand = command;
            return (skipRow) ? null : command;
        }