Examples of org.lealone.dbobject.index.Cursor

org.lealone.dbobject.index.Cursor
A cursor is a helper object to iterate through an index. For indexes are sorted (such as the b tree index), it can iterate to the very end of the index. For other indexes that don't support that (such as a hash index), only one row is returned. The cursor is initially positioned before the first row, that means next() must be called before accessing data.

        data.session = systemSession;
        meta = mainSchema.createTable(data);
        IndexColumn[] pkCols = IndexColumn.wrap(new Column[] { columnId });
        metaIdIndex = meta.addIndex(systemSession, "SYS_ID", 0, pkCols, IndexType.createPrimaryKey(false, false), true, null);


        Cursor cursor = metaIdIndex.find(systemSession, null, null);


        ArrayList<MetaRecord> records = New.arrayList();
        while (cursor.next()) {
            MetaRecord rec = new MetaRecord(cursor.get());
            objectIds.set(rec.getId());
            records.add(rec);
        }


        objectIds.set(0);

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    public synchronized void removeMeta(Session session, int id) {
        if (id > 0 && !starting) {
            SearchRow r = meta.getTemplateSimpleRow(false);
            r.setValue(0, ValueInt.get(id));
            boolean wasLocked = lockMeta(session);
            Cursor cursor = metaIdIndex.find(session, r, r);
            if (cursor.next()) {
                if (SysProperties.CHECK) {
                    if (lockMode != 0 && !wasLocked) {
                        throw DbException.throwInternalError();
                    }
                }
                Row found = cursor.get();
                meta.removeRow(session, found);
                if (isMultiVersion()) {
                    // TODO this should work without MVCC, but avoid risks at the
                    // moment
                    session.log(meta, UndoLogRecord.DELETE, found);

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    }


    private void checkMetaFree(Session session, int id) {
        SearchRow r = meta.getTemplateSimpleRow(false);
        r.setValue(0, ValueInt.get(id));
        Cursor cursor = metaIdIndex.find(session, r, r);
        if (cursor.next()) {
            DbException.throwInternalError();
        }
    }

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        return new ResultTempTable(this);
    }


    public int removeRow(Value[] values) {
        Row row = convertToRow(values);
        Cursor cursor = find(row);
        if (cursor != null) {
            row = cursor.get();
            table.removeRow(session, row);
        }
        return (int) table.getRowCount(session);
    }

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        return find(convertToRow(values)) != null;
    }


    public int addRow(Value[] values) {
        Row row = convertToRow(values);
        Cursor cursor = find(row);
        if (cursor == null) {
            table.addRow(session, row);
        }
        return (int) table.getRowCount(session);
    }

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        ValueArray data = ValueArray.get(values);
        return new Row(new Value[] { data }, Row.MEMORY_CALCULATE);
    }


    private Cursor find(Row row) {
        Cursor cursor = index.find(session, row, row);
        Value a = row.getValue(0);
        while (cursor.next()) {
            SearchRow found;
            found = cursor.getSearchRow();
            Value b = found.getValue(0);
            if (session.getDatabase().areEqual(a, b)) {
                return cursor;
            }
        }

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        if (index.needRebuild() && rowCount > 0) {
            try {
                Index scan = getScanIndex(session);
                long remaining = scan.getRowCount(session);
                long total = remaining;
                Cursor cursor = scan.find(session, null, null);
                long i = 0;
                int bufferSize = (int) Math.min(rowCount, Constants.DEFAULT_MAX_MEMORY_ROWS);
                ArrayList<Row> buffer = New.arrayList(bufferSize);
                String n = getName() + ":" + index.getName();
                int t = MathUtils.convertLongToInt(total);
                while (cursor.next()) {
                    database.setProgress(DatabaseEventListener.STATE_CREATE_INDEX, n, MathUtils.convertLongToInt(i++), t);
                    Row row = cursor.get();
                    buffer.add(row);
                    if (buffer.size() >= bufferSize) {
                        addRowsToIndex(session, buffer, index);
                    }
                    remaining--;

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                Index index = getColumnIndex();
                int sortType = index.getIndexColumns()[0].sortType;
                if ((sortType & SortOrder.DESCENDING) != 0) {
                    first = !first;
                }
                Cursor cursor = index.findFirstOrLast(session, first);
                SearchRow row = cursor.getSearchRow();
                Value v;
                if (row == null) {
                    v = ValueNull.INSTANCE;
                } else {
                    v = row.getValue(index.getColumns()[0].getColumnId());

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                Index index = getColumnIndex();
                int sortType = index.getIndexColumns()[0].sortType;
                if ((sortType & SortOrder.DESCENDING) != 0) {
                    first = !first;
                }
                Cursor cursor = index.findFirstOrLast(session, first);
                SearchRow row = cursor.getSearchRow();
                Value v;
                if (row == null) {
                    v = ValueNull.INSTANCE;
                } else {
                    v = row.getValue(index.getColumns()[0].getColumnId());

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    }


    private boolean existsRow(Session session, Index searchIndex, SearchRow check, Row excluding) {
        Table searchTable = searchIndex.getTable();
        searchTable.lock(session, false, false);
        Cursor cursor = searchIndex.find(session, check, check);
        while (cursor.next()) {
            SearchRow found;
            found = cursor.getSearchRow();
            if (excluding != null && found.getKey() == excluding.getKey()) {
                continue;
            }
            Column[] cols = searchIndex.getColumns();
            boolean allEqual = true;

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org.lealone.command.dml.Select

org.lealone.dbobject.constraint.ConstraintReferential

org.lealone.dbobject.table.TableBase

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org.lealone.result.ResultTempTable

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