private IReadOnlyList GetUserTableColumns()

in src/TriggerBinding/SqlTriggerListener.cs [214:266]
45 lines of code
5 McCabe index (conditional complexity)

        private IReadOnlyList<string> GetUserTableColumns(SqlConnection connection, int userTableId, CancellationToken cancellationToken)
        {
            const int NameIndex = 0, TypeIndex = 1, IsAssemblyTypeIndex = 2;
            string getUserTableColumnsQuery = $@"
                SELECT
                    c.name,
                    t.name,
                    t.is_assembly_type
                FROM sys.columns AS c
                INNER JOIN sys.types AS t ON c.user_type_id = t.user_type_id
                WHERE c.object_id = {userTableId};
            ";

            using (var getUserTableColumnsCommand = new SqlCommand(getUserTableColumnsQuery, connection))
            using (SqlDataReader reader = getUserTableColumnsCommand.ExecuteReaderWithLogging(this._logger))
            {
                var userTableColumns = new List<string>();
                var userDefinedTypeColumns = new List<(string name, string type)>();

                while (reader.Read())
                {
                    cancellationToken.ThrowIfCancellationRequested();
                    string columnName = reader.GetString(NameIndex);
                    string columnType = reader.GetString(TypeIndex);
                    bool isAssemblyType = reader.GetBoolean(IsAssemblyTypeIndex);

                    userTableColumns.Add(columnName);

                    if (isAssemblyType)
                    {
                        userDefinedTypeColumns.Add((columnName, columnType));
                    }
                }

                if (userDefinedTypeColumns.Count > 0)
                {
                    string columnNamesAndTypes = string.Join(", ", userDefinedTypeColumns.Select(col => $"'{col.name}' (type: {col.type})"));
                    throw new InvalidOperationException($"Found column(s) with unsupported type(s): {columnNamesAndTypes} in table: '{this._userTable.FullName}'.");
                }

                var conflictingColumnNames = userTableColumns.Intersect(ReservedColumnNames).ToList();

                if (conflictingColumnNames.Count > 0)
                {
                    string columnNames = string.Join(", ", conflictingColumnNames.Select(col => $"'{col}'"));
                    throw new InvalidOperationException($"Found reserved column name(s): {columnNames} in table: '{this._userTable.FullName}'." +
                        " Please rename them to be able to use trigger binding.");
                }

                this._logger.LogDebug($"GetUserTableColumns ColumnNames = {string.Join(", ", userTableColumns.Select(col => $"'{col}'"))}.");
                return userTableColumns;
            }
        }