Examples with ColumnRef herddb.sql.expressions.ColumnRef used on opensource projects

Example 1 with ColumnRef

use of herddb.sql.expressions.ColumnRef in project herddb by diennea.

the class JSQLParserPlanner method planAggregate.

private PlannerOp planAggregate(List<SelectExpressionItem> fieldList, OpSchema inputSchema, PlannerOp input, OpSchema originalTableSchema, GroupByElement groupBy) {
    List<Column> outputSchemaKeysInGroupBy = new ArrayList<>();
    List<String> fieldnamesKeysInGroupBy = new ArrayList<>();
    List<Column> outputSchemaAggregationResults = new ArrayList<>();
    List<String> fieldnamesAggregationResults = new ArrayList<>();
    List<Integer> projectionAggregationResults = new ArrayList<>();
    List<List<Integer>> argLists = new ArrayList<>();
    List<String> aggtypes = new ArrayList<>();
    List<Column> originalOutputSchema = new ArrayList<>();
    List<String> originalFieldNames = new ArrayList<>();
    Set<String> nonAggregateColumns = new HashSet<>();
    int k = 0;
    for (SelectExpressionItem sel : fieldList) {
        Alias alias = sel.getAlias();
        String fieldName = null;
        if (alias != null) {
            checkSupported(alias.getAliasColumns() == null);
            fieldName = fixMySqlBackTicks(alias.getName().toLowerCase());
        }
        Expression exp = sel.getExpression();
        Function fn = SQLParserExpressionCompiler.detectAggregatedFunction(exp);
        if (fn != null) {
            int type = SQLParserExpressionCompiler.getAggregateFunctionType(exp, inputSchema);
            ColumnRef additionalColumn = SQLParserExpressionCompiler.getAggregateFunctionArgument(fn, inputSchema);
            aggtypes.add(fixMySqlBackTicks(fn.getName().toLowerCase()));
            if (additionalColumn != null) {
                // SELECT min(col) -> we have to add "col" to the scan
                IntHolder pos = new IntHolder();
                findColumnInSchema(additionalColumn.tableName, fixMySqlBackTicks(additionalColumn.name), originalTableSchema, pos);
                checkSupported(pos.value >= 0);
                argLists.add(Collections.singletonList(pos.value));
            } else {
                argLists.add(Collections.emptyList());
            }
            if (fieldName == null) {
                fieldName = "expr$" + k;
            }
            Column col = Column.column(fieldName, type);
            outputSchemaAggregationResults.add(col);
            originalFieldNames.add(fieldName);
            originalOutputSchema.add(col);
            fieldnamesAggregationResults.add(fieldName);
            projectionAggregationResults.add(k);
        } else if (exp instanceof net.sf.jsqlparser.schema.Column) {
            net.sf.jsqlparser.schema.Column colRef = (net.sf.jsqlparser.schema.Column) exp;
            String tableAlias = extractTableName(colRef);
            ColumnRef colInSchema = findColumnInSchema(tableAlias, fixMySqlBackTicks(colRef.getColumnName()), inputSchema, new IntHolder());
            checkSupported(colInSchema != null);
            if (fieldName == null) {
                fieldName = colInSchema.name;
            }
            Column col = Column.column(fieldName, colInSchema.type);
            originalFieldNames.add(fieldName);
            originalOutputSchema.add(col);
            nonAggregateColumns.add(fieldName);
        } else {
            checkSupported(false);
        }
        k++;
    }
    // GROUP BY
    List<Integer> groupedFieldsIndexes = new ArrayList<>();
    List<Integer> projectionForGroupByFields = new ArrayList<>();
    if (groupBy != null) {
        checkSupported(groupBy.getGroupingSets() == null || groupBy.getGroupingSets().isEmpty());
        int posInGroupBy = 0;
        for (Expression exp : groupBy.getGroupByExpressions()) {
            if (exp instanceof net.sf.jsqlparser.schema.Column) {
                net.sf.jsqlparser.schema.Column colRef = (net.sf.jsqlparser.schema.Column) exp;
                String tableName = extractTableName(colRef);
                IntHolder pos = new IntHolder();
                ColumnRef colInSchema = findColumnInSchema(tableName, fixMySqlBackTicks(colRef.getColumnName()), inputSchema, pos);
                checkSupported(colInSchema != null);
                groupedFieldsIndexes.add(pos.value);
                fieldnamesKeysInGroupBy.add(fixMySqlBackTicks(colRef.getColumnName()));
                outputSchemaKeysInGroupBy.add(colInSchema.toColumn());
                projectionForGroupByFields.add(posInGroupBy);
            } else {
                checkSupported(false);
            }
            posInGroupBy++;
        }
    } else {
        // -> column MUST be in GROUP BY !
        for (String s : nonAggregateColumns) {
            throw new StatementExecutionException("field " + s + " MUST appear in GROUP BY clause");
        }
    }
    PlannerOp op;
    if (!groupedFieldsIndexes.isEmpty()) {
        // this is tricky,
        // the AggregateOp always create a result in the form of
        // FIELD1,FIELD2......AGG1,AGG2
        // Basically it puts all of the results of the aggregation to the right
        // So we have to add a projection that makes the resultset appear
        // as it is defined in the SELECT clause
        List<Column> outputSchema = new ArrayList<>();
        outputSchema.addAll(outputSchemaKeysInGroupBy);
        outputSchema.addAll(outputSchemaAggregationResults);
        Column[] outputSchemaArray = outputSchema.toArray(new Column[0]);
        List<String> aggreateFieldNames = new ArrayList<>();
        aggreateFieldNames.addAll(fieldnamesKeysInGroupBy);
        aggreateFieldNames.addAll(fieldnamesAggregationResults);
        op = new AggregateOp(input, aggreateFieldNames.toArray(new String[0]), outputSchemaArray, aggtypes.toArray(new String[0]), argLists, groupedFieldsIndexes);
        String[] reodereded = originalFieldNames.toArray(new String[0]);
        int[] projections = new int[originalFieldNames.size()];
        int i = 0;
        for (int pos : projectionForGroupByFields) {
            projections[pos] = i++;
        }
        for (int pos : projectionAggregationResults) {
            projections[pos] = i++;
        }
        ProjectOp.ZeroCopyProjection projection = new ProjectOp.ZeroCopyProjection(reodereded, originalOutputSchema.toArray(new Column[0]), projections);
        op = new ProjectOp(projection, op);
    } else {
        // no "GROUP BY", so no need for an additional projection
        // this is the SELECT COUNT(*) FROM TABLE case
        op = new AggregateOp(input, originalFieldNames.toArray(new String[0]), originalOutputSchema.toArray(new Column[0]), aggtypes.toArray(new String[0]), argLists, groupedFieldsIndexes);
    }
    return op;
}

Example 2 with ColumnRef

use of herddb.sql.expressions.ColumnRef in project herddb by diennea.

the class JSQLParserPlanner method buildProjection.

private Projection buildProjection(final List<SelectExpressionItem> projects, final boolean allowIdentity, final OpSchema tableSchema) {
    boolean allowZeroCopyProjection = true;
    List<CompiledSQLExpression> fields = new ArrayList<>(projects.size());
    Column[] columns = new Column[projects.size()];
    String[] fieldNames = new String[columns.length];
    int i = 0;
    int[] zeroCopyProjections = new int[fieldNames.length];
    boolean identity = allowIdentity && tableSchema != null && tableSchema.columns.length == fieldNames.length;
    for (SelectExpressionItem node : projects) {
        int type = ColumnTypes.ANYTYPE;
        CompiledSQLExpression exp;
        String alias = null;
        if (node.getAlias() != null) {
            alias = fixMySqlBackTicks(node.getAlias().getName().toLowerCase());
            checkSupported(node.getAlias().getAliasColumns() == null);
        }
        if (node.getExpression() instanceof net.sf.jsqlparser.schema.Column && !isBooleanLiteral((net.sf.jsqlparser.schema.Column) node.getExpression())) {
            net.sf.jsqlparser.schema.Column col = (net.sf.jsqlparser.schema.Column) node.getExpression();
            // checkSupported(col.getTable() == null);
            String columnName = fixMySqlBackTicks(col.getColumnName());
            String tableAlias = extractTableName(col);
            if (alias == null) {
                alias = columnName;
            }
            IntHolder indexInSchema = new IntHolder(-1);
            ColumnRef found = findColumnInSchema(tableAlias, columnName, tableSchema, indexInSchema);
            if (indexInSchema.value == -1 || found == null) {
                String nameInError = tableAlias != null ? tableAlias + "." + columnName : columnName;
                throw new StatementExecutionException("Column " + nameInError + " not found in target table (schema " + tableSchema + ")");
            }
            exp = new AccessCurrentRowExpression(indexInSchema.value, found.type);
            type = found.type;
        } else {
            exp = SQLParserExpressionCompiler.compileExpression(node.getExpression(), tableSchema);
            if (alias == null) {
                alias = "col" + i;
            }
        }
        if (exp instanceof AccessCurrentRowExpression) {
            AccessCurrentRowExpression accessCurrentRowExpression = (AccessCurrentRowExpression) exp;
            int mappedIndex = accessCurrentRowExpression.getIndex();
            zeroCopyProjections[i] = mappedIndex;
            if (i != mappedIndex) {
                identity = false;
            }
        } else {
            allowZeroCopyProjection = false;
        }
        fields.add(exp);
        Column col = Column.column(alias, type);
        identity = identity && col.name.equals(tableSchema.columns[i].name);
        fieldNames[i] = alias;
        columns[i++] = col;
    }
    if (allowZeroCopyProjection) {
        if (identity) {
            return Projection.IDENTITY(fieldNames, columns);
        }
        return new ProjectOp.ZeroCopyProjection(fieldNames, columns, zeroCopyProjections);
    } else {
        return new ProjectOp.BasicProjection(fieldNames, columns, fields);
    }
}

Example 3 with ColumnRef

use of herddb.sql.expressions.ColumnRef in project herddb by diennea.

the class JSQLParserPlanner method getTableSchema.

private OpSchema getTableSchema(String defaultTableSpace, net.sf.jsqlparser.schema.Table table) {
    String tableSpace = table.getSchemaName();
    if (tableSpace == null) {
        tableSpace = defaultTableSpace;
    }
    tableSpace = fixMySqlBackTicks(tableSpace);
    TableSpaceManager tableSpaceManager = getTableSpaceManager(tableSpace);
    if (tableSpaceManager == null) {
        clearCache();
        throw new StatementExecutionException("tablespace " + defaultTableSpace + " is not available");
    }
    String tableName = fixMySqlBackTicks(table.getName().toLowerCase());
    AbstractTableManager tableManager = tableSpaceManager.getTableManager(tableName);
    if (tableManager == null) {
        throw new TableDoesNotExistException("no table " + tableName + " here for " + tableSpace);
    }
    Table tableImpl = tableManager.getTable();
    String aliasTable = tableName;
    if (table.getAlias() != null) {
        aliasTable = fixMySqlBackTicks(table.getAlias().getName());
        checkSupported(table.getAlias().getAliasColumns() == null);
    }
    ColumnRef[] refs = new ColumnRef[tableImpl.columns.length];
    for (int i = 0; i < refs.length; i++) {
        refs[i] = new ColumnRef(aliasTable, tableImpl.columns[i]);
    }
    return new OpSchema(tableSpace, tableName, aliasTable, tableImpl.columnNames, refs);
}

Example 4 with ColumnRef

use of herddb.sql.expressions.ColumnRef in project herddb by diennea.

the class JSQLParserPlanner method buildSelectBody.

private PlannerOp buildSelectBody(String defaultTableSpace, int maxRows, SelectBody selectBody, boolean forceScan) throws StatementExecutionException {
    if (selectBody instanceof SetOperationList) {
        SetOperationList list = (SetOperationList) selectBody;
        return buildSetOperationList(defaultTableSpace, maxRows, list, forceScan);
    }
    checkSupported(selectBody instanceof PlainSelect, selectBody.getClass().getName());
    PlainSelect plainSelect = (PlainSelect) selectBody;
    checkSupported(!plainSelect.getMySqlHintStraightJoin());
    checkSupported(!plainSelect.getMySqlSqlCalcFoundRows());
    checkSupported(!plainSelect.getMySqlSqlNoCache());
    checkSupported(plainSelect.getDistinct() == null);
    checkSupported(plainSelect.getFetch() == null);
    checkSupported(plainSelect.getFirst() == null);
    checkSupported(plainSelect.getForUpdateTable() == null);
    checkSupported(plainSelect.getForXmlPath() == null);
    checkSupported(plainSelect.getHaving() == null);
    checkSupported(plainSelect.getIntoTables() == null);
    checkSupported(plainSelect.getOffset() == null);
    checkSupported(plainSelect.getOptimizeFor() == null);
    checkSupported(plainSelect.getOracleHierarchical() == null);
    checkSupported(plainSelect.getOracleHint() == null);
    checkSupported(plainSelect.getSkip() == null);
    checkSupported(plainSelect.getWait() == null);
    checkSupported(plainSelect.getKsqlWindow() == null);
    FromItem fromItem = plainSelect.getFromItem();
    checkSupported(fromItem instanceof net.sf.jsqlparser.schema.Table);
    OpSchema primaryTableSchema = getTableSchema(defaultTableSpace, (net.sf.jsqlparser.schema.Table) fromItem);
    OpSchema[] joinedTables = new OpSchema[0];
    int totalJoinOutputFieldsCount = primaryTableSchema.columns.length;
    if (plainSelect.getJoins() != null) {
        joinedTables = new OpSchema[plainSelect.getJoins().size()];
        int i = 0;
        for (Join join : plainSelect.getJoins()) {
            checkSupported(!join.isApply());
            checkSupported(!join.isCross());
            checkSupported(!join.isFull() || (join.isFull() && join.isOuter()));
            checkSupported(!join.isSemi());
            checkSupported(!join.isStraight());
            checkSupported(!join.isWindowJoin());
            checkSupported(join.getJoinWindow() == null);
            checkSupported(join.getUsingColumns() == null);
            FromItem rightItem = join.getRightItem();
            checkSupported(rightItem instanceof net.sf.jsqlparser.schema.Table);
            OpSchema joinedTable = getTableSchema(defaultTableSpace, (net.sf.jsqlparser.schema.Table) rightItem);
            joinedTables[i++] = joinedTable;
            totalJoinOutputFieldsCount += joinedTable.columns.length;
        }
    }
    int pos = 0;
    String[] joinOutputFieldnames = new String[totalJoinOutputFieldsCount];
    ColumnRef[] joinOutputColumns = new ColumnRef[totalJoinOutputFieldsCount];
    System.arraycopy(primaryTableSchema.columnNames, 0, joinOutputFieldnames, 0, primaryTableSchema.columnNames.length);
    System.arraycopy(primaryTableSchema.columns, 0, joinOutputColumns, 0, primaryTableSchema.columns.length);
    pos += primaryTableSchema.columnNames.length;
    for (OpSchema joinedTable : joinedTables) {
        System.arraycopy(joinedTable.columnNames, 0, joinOutputFieldnames, pos, joinedTable.columnNames.length);
        System.arraycopy(joinedTable.columns, 0, joinOutputColumns, pos, joinedTable.columns.length);
        pos += joinedTable.columnNames.length;
    }
    OpSchema currentSchema = primaryTableSchema;
    // single JOIN only at the moment
    checkSupported(joinedTables.length <= 1);
    if (joinedTables.length > 0) {
        currentSchema = new OpSchema(primaryTableSchema.tableSpace, null, null, joinOutputFieldnames, joinOutputColumns);
    }
    List<SelectItem> selectItems = plainSelect.getSelectItems();
    checkSupported(!selectItems.isEmpty());
    Predicate predicate = null;
    TupleComparator comparator = null;
    ScanLimits limits = null;
    boolean identityProjection = false;
    Projection projection;
    List<SelectExpressionItem> selectedFields = new ArrayList<>(selectItems.size());
    boolean containsAggregatedFunctions = false;
    if (selectItems.size() == 1 && selectItems.get(0) instanceof AllColumns) {
        projection = Projection.IDENTITY(currentSchema.columnNames, ColumnRef.toColumnsArray(currentSchema.columns));
        identityProjection = true;
    } else {
        checkSupported(!selectItems.isEmpty());
        for (SelectItem item : selectItems) {
            if (item instanceof SelectExpressionItem) {
                SelectExpressionItem selectExpressionItem = (SelectExpressionItem) item;
                selectedFields.add(selectExpressionItem);
                if (SQLParserExpressionCompiler.detectAggregatedFunction(selectExpressionItem.getExpression()) != null) {
                    containsAggregatedFunctions = true;
                }
            } else if (item instanceof AllTableColumns) {
                // expand  alias.* to the full list of columns (according to pyhsical schema!)
                AllTableColumns allTablesColumn = (AllTableColumns) item;
                net.sf.jsqlparser.schema.Table table = allTablesColumn.getTable();
                String tableName = fixMySqlBackTicks(table.getName());
                boolean found = false;
                if (primaryTableSchema.isTableOrAlias(tableName)) {
                    for (ColumnRef col : primaryTableSchema.columns) {
                        net.sf.jsqlparser.schema.Column c = new net.sf.jsqlparser.schema.Column(table, col.name);
                        SelectExpressionItem selectExpressionItem = new SelectExpressionItem(c);
                        selectedFields.add(selectExpressionItem);
                        found = true;
                    }
                } else {
                    for (OpSchema joinedTableSchema : joinedTables) {
                        if (joinedTableSchema.isTableOrAlias(tableName)) {
                            for (ColumnRef col : joinedTableSchema.columns) {
                                net.sf.jsqlparser.schema.Column c = new net.sf.jsqlparser.schema.Column(table, col.name);
                                SelectExpressionItem selectExpressionItem = new SelectExpressionItem(c);
                                selectedFields.add(selectExpressionItem);
                            }
                            found = true;
                            break;
                        }
                    }
                }
                if (!found) {
                    checkSupported(false, "Bad table ref " + tableName + ".*");
                }
            } else {
                checkSupported(false);
            }
        }
        if (!containsAggregatedFunctions) {
            // building the projection
            // we have the current physical schema, we can create references by position (as Calcite does)
            // in order to not need accessing columns by name and also making it easier to support
            // ZeroCopyProjections
            projection = buildProjection(selectedFields, true, currentSchema);
        } else {
            // start by full table scan, the AggregateOp operator will create the final projection
            projection = Projection.IDENTITY(currentSchema.columnNames, ColumnRef.toColumnsArray(currentSchema.columns));
            identityProjection = true;
        }
    }
    TableSpaceManager tableSpaceManager = this.manager.getTableSpaceManager(primaryTableSchema.tableSpace);
    AbstractTableManager tableManager = tableSpaceManager.getTableManager(primaryTableSchema.name);
    Table tableImpl = tableManager.getTable();
    CompiledSQLExpression whereExpression = null;
    if (plainSelect.getWhere() != null) {
        whereExpression = SQLParserExpressionCompiler.compileExpression(plainSelect.getWhere(), currentSchema);
        if (joinedTables.length == 0 && whereExpression != null) {
            SQLRecordPredicate sqlWhere = new SQLRecordPredicate(tableImpl, null, whereExpression);
            IndexUtils.discoverIndexOperations(primaryTableSchema.tableSpace, whereExpression, tableImpl, sqlWhere, selectBody, tableSpaceManager);
            predicate = sqlWhere;
        }
    }
    // start with a TableScan + filters
    ScanStatement scan = new ScanStatement(primaryTableSchema.tableSpace, primaryTableSchema.name, Projection.IDENTITY(primaryTableSchema.columnNames, ColumnRef.toColumnsArray(primaryTableSchema.columns)), predicate, comparator, limits);
    scan.setTableDef(tableImpl);
    PlannerOp op = new BindableTableScanOp(scan);
    PlannerOp[] scanJoinedTables = new PlannerOp[joinedTables.length];
    int ji = 0;
    for (OpSchema joinedTable : joinedTables) {
        ScanStatement scanSecondaryTable = new ScanStatement(joinedTable.tableSpace, joinedTable.name, Projection.IDENTITY(joinedTable.columnNames, ColumnRef.toColumnsArray(joinedTable.columns)), null, null, null);
        scan.setTableDef(tableImpl);
        checkSupported(joinedTable.tableSpace.equalsIgnoreCase(primaryTableSchema.tableSpace));
        PlannerOp opSecondaryTable = new BindableTableScanOp(scanSecondaryTable);
        scanJoinedTables[ji++] = opSecondaryTable;
    }
    if (scanJoinedTables.length > 0) {
        // assuming only one JOIN clause
        Join joinClause = plainSelect.getJoins().get(0);
        List<CompiledSQLExpression> joinConditions = new ArrayList<>();
        if (joinClause.isNatural()) {
            // NATURAL join adds a constraint on every column with the same name
            List<CompiledSQLExpression> naturalJoinConstraints = new ArrayList<>();
            int posInRowLeft = 0;
            for (ColumnRef ref : primaryTableSchema.columns) {
                int posInRowRight = primaryTableSchema.columns.length;
                for (ColumnRef ref2 : joinedTables[0].columns) {
                    // assuming only one join
                    if (ref2.name.equalsIgnoreCase(ref.name)) {
                        CompiledSQLExpression equals = new CompiledEqualsExpression(new AccessCurrentRowExpression(posInRowLeft, ref.type), new AccessCurrentRowExpression(posInRowRight, ref2.type));
                        naturalJoinConstraints.add(equals);
                    }
                    posInRowRight++;
                }
                posInRowLeft++;
            }
            CompiledSQLExpression naturalJoin = new CompiledMultiAndExpression(naturalJoinConstraints.toArray(new CompiledSQLExpression[0]));
            joinConditions.add(naturalJoin);
        }
        // handle "ON" clause
        Expression onExpression = joinClause.getOnExpression();
        if (onExpression != null) {
            // TODO: this works for INNER join, but not for LEFT/RIGHT joins
            CompiledSQLExpression onCondition = SQLParserExpressionCompiler.compileExpression(onExpression, currentSchema);
            joinConditions.add(onCondition);
        }
        op = new JoinOp(joinOutputFieldnames, ColumnRef.toColumnsArray(joinOutputColumns), new int[0], op, new int[0], scanJoinedTables[0], // generateNullsOnLeft
        joinClause.isRight() || (joinClause.isFull() && joinClause.isOuter()), // generateNullsOnRight
        joinClause.isLeft() || (joinClause.isFull() && joinClause.isOuter()), // mergeJoin
        false, // "ON" conditions
        joinConditions);
        // handle "WHERE" in case of JOIN
        if (whereExpression != null) {
            op = new FilterOp(op, whereExpression);
        }
    }
    // add aggregations
    if (containsAggregatedFunctions) {
        checkSupported(scanJoinedTables.length == 0);
        op = planAggregate(selectedFields, currentSchema, op, currentSchema, plainSelect.getGroupBy());
        currentSchema = new OpSchema(currentSchema.tableSpace, currentSchema.name, currentSchema.alias, ColumnRef.toColumnsRefsArray(currentSchema.name, op.getOutputSchema()));
    }
    // add order by
    if (plainSelect.getOrderByElements() != null) {
        op = planSort(op, currentSchema, plainSelect.getOrderByElements());
    }
    // add limit
    if (plainSelect.getLimit() != null) {
        checkSupported(scanJoinedTables.length == 0);
        // cannot mix LIMIT and TOP
        checkSupported(plainSelect.getTop() == null);
        Limit limit = plainSelect.getLimit();
        CompiledSQLExpression offset;
        if (limit.getOffset() != null) {
            offset = SQLParserExpressionCompiler.compileExpression(limit.getOffset(), currentSchema);
        } else {
            offset = new ConstantExpression(0, ColumnTypes.NOTNULL_LONG);
        }
        CompiledSQLExpression rowCount = null;
        if (limit.getRowCount() != null) {
            rowCount = SQLParserExpressionCompiler.compileExpression(limit.getRowCount(), currentSchema);
        }
        op = new LimitOp(op, rowCount, offset);
    }
    if (plainSelect.getTop() != null) {
        checkSupported(scanJoinedTables.length == 0);
        // cannot mix LIMIT and TOP
        checkSupported(plainSelect.getLimit() == null);
        Top limit = plainSelect.getTop();
        CompiledSQLExpression rowCount = null;
        if (limit.getExpression() != null) {
            rowCount = SQLParserExpressionCompiler.compileExpression(limit.getExpression(), currentSchema);
        }
        op = new LimitOp(op, rowCount, new ConstantExpression(0, ColumnTypes.NOTNULL_LONG));
    }
    if (!containsAggregatedFunctions && !identityProjection) {
        // add projection
        op = new ProjectOp(projection, op);
    }
    // additional maxrows from JDBC PreparedStatement
    if (maxRows > 0) {
        op = new LimitOp(op, new ConstantExpression(maxRows, ColumnTypes.NOTNULL_LONG), new ConstantExpression(0, ColumnTypes.NOTNULL_LONG)).optimize();
    }
    return op;
}