Examples with ResultInterface org.h2.result.ResultInterface used on opensource projects

Example 26 with ResultInterface

use of org.h2.result.ResultInterface in project h2database by h2database.

the class Query method query.

/**
 * Execute the query, writing the result to the target result.
 *
 * @param limit the maximum number of rows to return
 * @param target the target result (null will return the result)
 * @return the result set (if the target is not set).
 */
public final ResultInterface query(int limit, ResultTarget target) {
    if (isUnion()) {
        // right queries
        return queryWithoutCacheLazyCheck(limit, target);
    }
    fireBeforeSelectTriggers();
    if (noCache || !session.getDatabase().getOptimizeReuseResults() || session.isLazyQueryExecution()) {
        return queryWithoutCacheLazyCheck(limit, target);
    }
    Value[] params = getParameterValues();
    long now = session.getDatabase().getModificationDataId();
    if (isEverything(ExpressionVisitor.DETERMINISTIC_VISITOR)) {
        if (lastResult != null && !lastResult.isClosed() && limit == lastLimit) {
            if (sameResultAsLast(session, params, lastParameters, lastEvaluated)) {
                lastResult = lastResult.createShallowCopy(session);
                if (lastResult != null) {
                    lastResult.reset();
                    return lastResult;
                }
            }
        }
    }
    lastParameters = params;
    closeLastResult();
    ResultInterface r = queryWithoutCacheLazyCheck(limit, target);
    lastResult = r;
    this.lastEvaluated = now;
    lastLimit = limit;
    return r;
}

Example 27 with ResultInterface

use of org.h2.result.ResultInterface in project h2database by h2database.

the class ScriptCommand method queryMeta.

@Override
public ResultInterface queryMeta() {
    LocalResult r = createResult();
    r.done();
    return r;
}

Example 28 with ResultInterface

use of org.h2.result.ResultInterface in project h2database by h2database.

the class SelectUnion method queryMeta.

@Override
public ResultInterface queryMeta() {
    int columnCount = left.getColumnCount();
    LocalResult result = new LocalResult(session, expressionArray, columnCount);
    result.done();
    return result;
}

Example 29 with ResultInterface

use of org.h2.result.ResultInterface in project h2database by h2database.

the class SelectUnion method queryWithoutCache.

@Override
protected ResultInterface queryWithoutCache(int maxRows, ResultTarget target) {
    if (maxRows != 0) {
        // maxRows is set (maxRows 0 means no limit)
        int l;
        if (limitExpr == null) {
            l = -1;
        } else {
            Value v = limitExpr.getValue(session);
            l = v == ValueNull.INSTANCE ? -1 : v.getInt();
        }
        if (l < 0) {
            // for limitExpr, 0 means no rows, and -1 means no limit
            l = maxRows;
        } else {
            l = Math.min(l, maxRows);
        }
        limitExpr = ValueExpression.get(ValueInt.get(l));
    }
    if (session.getDatabase().getSettings().optimizeInsertFromSelect) {
        if (unionType == UnionType.UNION_ALL && target != null) {
            if (sort == null && !distinct && maxRows == 0 && offsetExpr == null && limitExpr == null) {
                left.query(0, target);
                right.query(0, target);
                return null;
            }
        }
    }
    int columnCount = left.getColumnCount();
    if (session.isLazyQueryExecution() && unionType == UnionType.UNION_ALL && !distinct && sort == null && !randomAccessResult && !isForUpdate && offsetExpr == null && isReadOnly()) {
        int limit = -1;
        if (limitExpr != null) {
            Value v = limitExpr.getValue(session);
            if (v != ValueNull.INSTANCE) {
                limit = v.getInt();
            }
        }
        // limit 0 means no rows
        if (limit != 0) {
            LazyResultUnion lazyResult = new LazyResultUnion(expressionArray, columnCount);
            if (limit > 0) {
                lazyResult.setLimit(limit);
            }
            return lazyResult;
        }
    }
    LocalResult result = new LocalResult(session, expressionArray, columnCount);
    if (sort != null) {
        result.setSortOrder(sort);
    }
    if (distinct) {
        left.setDistinct(true);
        right.setDistinct(true);
        result.setDistinct();
    }
    if (randomAccessResult) {
        result.setRandomAccess();
    }
    switch(unionType) {
        case UNION:
        case EXCEPT:
            left.setDistinct(true);
            right.setDistinct(true);
            result.setDistinct();
            break;
        case UNION_ALL:
            break;
        case INTERSECT:
            left.setDistinct(true);
            right.setDistinct(true);
            break;
        default:
            DbException.throwInternalError("type=" + unionType);
    }
    ResultInterface l = left.query(0);
    ResultInterface r = right.query(0);
    l.reset();
    r.reset();
    switch(unionType) {
        case UNION_ALL:
        case UNION:
            {
                while (l.next()) {
                    result.addRow(convert(l.currentRow(), columnCount));
                }
                while (r.next()) {
                    result.addRow(convert(r.currentRow(), columnCount));
                }
                break;
            }
        case EXCEPT:
            {
                while (l.next()) {
                    result.addRow(convert(l.currentRow(), columnCount));
                }
                while (r.next()) {
                    result.removeDistinct(convert(r.currentRow(), columnCount));
                }
                break;
            }
        case INTERSECT:
            {
                LocalResult temp = new LocalResult(session, expressionArray, columnCount);
                temp.setDistinct();
                temp.setRandomAccess();
                while (l.next()) {
                    temp.addRow(convert(l.currentRow(), columnCount));
                }
                while (r.next()) {
                    Value[] values = convert(r.currentRow(), columnCount);
                    if (temp.containsDistinct(values)) {
                        result.addRow(values);
                    }
                }
                temp.close();
                break;
            }
        default:
            DbException.throwInternalError("type=" + unionType);
    }
    if (offsetExpr != null) {
        result.setOffset(offsetExpr.getValue(session).getInt());
    }
    if (limitExpr != null) {
        Value v = limitExpr.getValue(session);
        if (v != ValueNull.INSTANCE) {
            result.setLimit(v.getInt());
        }
    }
    l.close();
    r.close();
    result.done();
    if (target != null) {
        while (result.next()) {
            target.addRow(result.currentRow());
        }
        result.close();
        return null;
    }
    return result;
}

Example 30 with ResultInterface

use of org.h2.result.ResultInterface in project h2database by h2database.

the class SessionRemote method readSerializationSettings.

/**
 * Read the serializer name from the persistent database settings.
 *
 * @return the serializer
 */
private String readSerializationSettings() {
    String javaObjectSerializerFQN = null;
    CommandInterface ci = prepareCommand("SELECT VALUE FROM INFORMATION_SCHEMA.SETTINGS " + " WHERE NAME='JAVA_OBJECT_SERIALIZER'", Integer.MAX_VALUE);
    try {
        ResultInterface result = ci.executeQuery(0, false);
        if (result.next()) {
            Value[] row = result.currentRow();
            javaObjectSerializerFQN = row[0].getString();
        }
    } finally {
        ci.close();
    }
    return javaObjectSerializerFQN;
}