Examples with ExpressionColumn org.h2.expression.ExpressionColumn used on opensource projects

Example 11 with ExpressionColumn

use of org.h2.expression.ExpressionColumn in project h2database by h2database.

the class TableFunction method getTable.

private ValueResultSet getTable(Session session, Expression[] argList, boolean onlyColumnList, boolean distinctRows) {
    int len = columnList.length;
    Expression[] header = new Expression[len];
    Database db = session.getDatabase();
    for (int i = 0; i < len; i++) {
        Column c = columnList[i];
        ExpressionColumn col = new ExpressionColumn(db, c);
        header[i] = col;
    }
    LocalResult result = new LocalResult(session, header, len);
    if (distinctRows) {
        result.setDistinct();
    }
    if (!onlyColumnList) {
        Value[][] list = new Value[len][];
        int rows = 0;
        for (int i = 0; i < len; i++) {
            Value v = argList[i].getValue(session);
            if (v == ValueNull.INSTANCE) {
                list[i] = new Value[0];
            } else {
                ValueArray array = (ValueArray) v.convertTo(Value.ARRAY);
                Value[] l = array.getList();
                list[i] = l;
                rows = Math.max(rows, l.length);
            }
        }
        for (int row = 0; row < rows; row++) {
            Value[] r = new Value[len];
            for (int j = 0; j < len; j++) {
                Value[] l = list[j];
                Value v;
                if (l.length <= row) {
                    v = ValueNull.INSTANCE;
                } else {
                    Column c = columnList[j];
                    v = l[row];
                    v = c.convert(v);
                    v = v.convertPrecision(c.getPrecision(), false);
                    v = v.convertScale(true, c.getScale());
                }
                r[j] = v;
            }
            result.addRow(r);
        }
    }
    result.done();
    return ValueResultSet.get(getSimpleResultSet(result, Integer.MAX_VALUE));
}

Example 12 with ExpressionColumn

use of org.h2.expression.ExpressionColumn in project h2database by h2database.

the class FullText method addColumnData.

private static void addColumnData(ArrayList<String> columns, ArrayList<String> data, Expression expr) {
    if (expr instanceof ConditionAndOr) {
        ConditionAndOr and = (ConditionAndOr) expr;
        Expression left = and.getExpression(true);
        Expression right = and.getExpression(false);
        addColumnData(columns, data, left);
        addColumnData(columns, data, right);
    } else {
        Comparison comp = (Comparison) expr;
        ExpressionColumn ec = (ExpressionColumn) comp.getExpression(true);
        ValueExpression ev = (ValueExpression) comp.getExpression(false);
        String columnName = ec.getColumnName();
        columns.add(columnName);
        if (ev == null) {
            data.add(null);
        } else {
            data.add(ev.getValue(null).getString());
        }
    }
}

Example 13 with ExpressionColumn

use of org.h2.expression.ExpressionColumn in project h2database by h2database.

the class FullTextLucene method search.

/**
 * Do the search.
 *
 * @param conn the database connection
 * @param text the query
 * @param limit the limit
 * @param offset the offset
 * @param data whether the raw data should be returned
 * @return the result set
 */
protected static ResultSet search(Connection conn, String text, int limit, int offset, boolean data) throws SQLException {
    SimpleResultSet result = createResultSet(data);
    if (conn.getMetaData().getURL().startsWith("jdbc:columnlist:")) {
        // this is just to query the result set columns
        return result;
    }
    if (text == null || text.trim().length() == 0) {
        return result;
    }
    try {
        IndexAccess access = getIndexAccess(conn);
        // take a reference as the searcher may change
        IndexSearcher searcher = access.getSearcher();
        try {
            // reuse the same analyzer; it's thread-safe;
            // also allows subclasses to control the analyzer used.
            Analyzer analyzer = access.writer.getAnalyzer();
            QueryParser parser = new QueryParser(Version.LUCENE_30, LUCENE_FIELD_DATA, analyzer);
            Query query = parser.parse(text);
            // Lucene 3 insists on a hard limit and will not provide
            // a total hits value. Take at least 100 which is
            // an optimal limit for Lucene as any more
            // will trigger writing results to disk.
            int maxResults = (limit == 0 ? 100 : limit) + offset;
            TopDocs docs = searcher.search(query, maxResults);
            if (limit == 0) {
                limit = docs.totalHits;
            }
            for (int i = 0, len = docs.scoreDocs.length; i < limit && i + offset < docs.totalHits && i + offset < len; i++) {
                ScoreDoc sd = docs.scoreDocs[i + offset];
                Document doc = searcher.doc(sd.doc);
                float score = sd.score;
                String q = doc.get(LUCENE_FIELD_QUERY);
                if (data) {
                    int idx = q.indexOf(" WHERE ");
                    JdbcConnection c = (JdbcConnection) conn;
                    Session session = (Session) c.getSession();
                    Parser p = new Parser(session);
                    String tab = q.substring(0, idx);
                    ExpressionColumn expr = (ExpressionColumn) p.parseExpression(tab);
                    String schemaName = expr.getOriginalTableAliasName();
                    String tableName = expr.getColumnName();
                    q = q.substring(idx + " WHERE ".length());
                    Object[][] columnData = parseKey(conn, q);
                    result.addRow(schemaName, tableName, columnData[0], columnData[1], score);
                } else {
                    result.addRow(q, score);
                }
            }
        } finally {
            access.returnSearcher(searcher);
        }
    } catch (Exception e) {
        throw convertException(e);
    }
    return result;
}

Example 14 with ExpressionColumn

use of org.h2.expression.ExpressionColumn in project h2database by h2database.

the class AggregateDataMedian method getMedianColumnIndex.

/**
 * Get the index (if any) for the column specified in the median aggregate.
 *
 * @param on the expression (usually a column expression)
 * @return the index, or null
 */
static Index getMedianColumnIndex(Expression on) {
    if (on instanceof ExpressionColumn) {
        ExpressionColumn col = (ExpressionColumn) on;
        Column column = col.getColumn();
        TableFilter filter = col.getTableFilter();
        if (filter != null) {
            Table table = filter.getTable();
            ArrayList<Index> indexes = table.getIndexes();
            Index result = null;
            if (indexes != null) {
                boolean nullable = column.isNullable();
                for (int i = 1, size = indexes.size(); i < size; i++) {
                    Index index = indexes.get(i);
                    if (!index.canFindNext()) {
                        continue;
                    }
                    if (!index.isFirstColumn(column)) {
                        continue;
                    }
                    // Prefer index without nulls last for nullable columns
                    if (result == null || result.getColumns().length > index.getColumns().length || nullable && isNullsLast(result) && !isNullsLast(index)) {
                        result = index;
                    }
                }
            }
            return result;
        }
    }
    return null;
}

Example 15 with ExpressionColumn

use of org.h2.expression.ExpressionColumn in project h2database by h2database.

the class AggregateDataMedian method getResultFromIndex.

/**
 * Get the result from the index.
 *
 * @param session the session
 * @param on the expression
 * @param dataType the data type
 * @return the result
 */
static Value getResultFromIndex(Session session, Expression on, int dataType) {
    Index index = getMedianColumnIndex(on);
    long count = index.getRowCount(session);
    if (count == 0) {
        return ValueNull.INSTANCE;
    }
    Cursor cursor = index.find(session, null, null);
    cursor.next();
    int columnId = index.getColumns()[0].getColumnId();
    ExpressionColumn expr = (ExpressionColumn) on;
    if (expr.getColumn().isNullable()) {
        boolean hasNulls = false;
        SearchRow row;
        // will be used to read values.
        while (count > 0) {
            row = cursor.getSearchRow();
            if (row == null) {
                return ValueNull.INSTANCE;
            }
            if (row.getValue(columnId) == ValueNull.INSTANCE) {
                count--;
                cursor.next();
                hasNulls = true;
            } else {
                break;
            }
        }
        if (count == 0) {
            return ValueNull.INSTANCE;
        }
        // cursor to count nulls at the end.
        if (!hasNulls && isNullsLast(index)) {
            TableFilter tableFilter = expr.getTableFilter();
            SearchRow check = tableFilter.getTable().getTemplateSimpleRow(true);
            check.setValue(columnId, ValueNull.INSTANCE);
            Cursor nullsCursor = index.find(session, check, check);
            while (nullsCursor.next()) {
                count--;
            }
            if (count <= 0) {
                return ValueNull.INSTANCE;
            }
        }
    }
    long skip = (count - 1) / 2;
    for (int i = 0; i < skip; i++) {
        cursor.next();
    }
    SearchRow row = cursor.getSearchRow();
    if (row == null) {
        return ValueNull.INSTANCE;
    }
    Value v = row.getValue(columnId);
    if (v == ValueNull.INSTANCE) {
        return v;
    }
    if ((count & 1) == 0) {
        cursor.next();
        row = cursor.getSearchRow();
        if (row == null) {
            return v;
        }
        Value v2 = row.getValue(columnId);
        if (v2 == ValueNull.INSTANCE) {
            return v;
        }
        return getMedian(v, v2, dataType, session.getDatabase().getCompareMode());
    }
    return v;
}