Examples with Value com.wplatform.ddal.value.Value used on opensource projects

Example 1 with Value

use of com.wplatform.ddal.value.Value in project jdbc-shards by wplatform.

the class Query method prepareOrder.

/**
     * Create a {@link SortOrder} object given the list of {@link SelectOrderBy}
     * objects. The expression list is extended if necessary.
     *
     * @param orderList       a list of {@link SelectOrderBy} elements
     * @param expressionCount the number of columns in the query
     * @return the {@link SortOrder} object
     */
public SortOrder prepareOrder(ArrayList<SelectOrderBy> orderList, int expressionCount) {
    int size = orderList.size();
    int[] index = new int[size];
    int[] sortType = new int[size];
    for (int i = 0; i < size; i++) {
        SelectOrderBy o = orderList.get(i);
        int idx;
        boolean reverse = false;
        Expression expr = o.columnIndexExpr;
        Value v = expr.getValue(null);
        if (v == ValueNull.INSTANCE) {
            // parameter not yet set - order by first column
            idx = 0;
        } else {
            idx = v.getInt();
            if (idx < 0) {
                reverse = true;
                idx = -idx;
            }
            idx -= 1;
            if (idx < 0 || idx >= expressionCount) {
                throw DbException.get(ErrorCode.ORDER_BY_NOT_IN_RESULT, "" + (idx + 1));
            }
        }
        index[i] = idx;
        boolean desc = o.descending;
        if (reverse) {
            desc = !desc;
        }
        int type = desc ? SortOrder.DESCENDING : SortOrder.ASCENDING;
        if (o.nullsFirst) {
            type += SortOrder.NULLS_FIRST;
        } else if (o.nullsLast) {
            type += SortOrder.NULLS_LAST;
        }
        sortType[i] = type;
    }
    return new SortOrder(session.getDatabase(), index, sortType, orderList);
}

Example 2 with Value

use of com.wplatform.ddal.value.Value in project jdbc-shards by wplatform.

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 LocalResult query(int limit, ResultTarget target) {
    if (noCache) {
        return queryWithoutCache(limit, target);
    }
    Value[] params = getParameterValues();
    if (isEverything(ExpressionVisitor.DETERMINISTIC_VISITOR)) {
        if (lastResult != null && !lastResult.isClosed() && limit == lastLimit) {
            if (sameResultAsLast(session, params, lastParameters)) {
                lastResult = lastResult.createShallowCopy(session);
                if (lastResult != null) {
                    lastResult.reset();
                    return lastResult;
                }
            }
        }
    }
    lastParameters = params;
    closeLastResult();
    LocalResult r = queryWithoutCache(limit, target);
    lastResult = r;
    lastLimit = limit;
    return r;
}

Example 3 with Value

use of com.wplatform.ddal.value.Value in project jdbc-shards by wplatform.

the class ConditionInConstantSet method getValue.

@Override
public Value getValue(Session session) {
    Value x = left.getValue(session);
    if (x == ValueNull.INSTANCE) {
        return x;
    }
    boolean result = valueSet.contains(x);
    if (!result) {
        boolean setHasNull = valueSet.contains(ValueNull.INSTANCE);
        if (setHasNull) {
            return ValueNull.INSTANCE;
        }
    }
    return ValueBoolean.get(result);
}

Example 4 with Value

use of com.wplatform.ddal.value.Value in project jdbc-shards by wplatform.

the class ConditionInSelect method exportParameters.

@Override
public String exportParameters(TableFilter filter, List<Value> container) {
    Session session = filter.getSession();
    LocalResult rows = query(session);
    if (rows.getRowCount() > 0) {
        StatementBuilder buff = new StatementBuilder();
        buff.append('(').append(left.exportParameters(filter, container)).append(' ');
        if (all) {
            //由于all代表全部，所以<all表示小于子查询中返回全部值中的最小值；
            //>all表示大于子查询中返回全部值中的最大值。
            buff.append(Comparison.getCompareOperator(compareType)).append(" ALL");
        } else {
            if (compareType == Comparison.EQUAL) {
                buff.append("IN");
            } else {
                //<any可以理解为小于子查询中返回的任意一个值，因此只要小于最大值即可
                //>any可以理解为大于子查询中返回的任意一个值，因此只要大于最小值即可
                buff.append(Comparison.getCompareOperator(compareType)).append(" ANY");
            }
        }
        buff.append("(");
        while (rows.next()) {
            buff.appendExceptFirst(",");
            buff.append("?");
            Value r = rows.currentRow()[0];
            container.add(r);
        }
        buff.append("))");
        return buff.toString();
    } else {
        return "1 = 0";
    }
}

Example 5 with Value

use of com.wplatform.ddal.value.Value in project jdbc-shards by wplatform.

the class ConditionInSelect method getValue.

@Override
public Value getValue(Session session) {
    LocalResult rows = query(session);
    try {
        Value l = left.getValue(session);
        if (rows.getRowCount() == 0) {
            return ValueBoolean.get(all);
        } else if (l == ValueNull.INSTANCE) {
            return l;
        }
        if (!session.getDatabase().getSettings().optimizeInSelect) {
            return getValueSlow(rows, l);
        }
        if (all || (compareType != Comparison.EQUAL && compareType != Comparison.EQUAL_NULL_SAFE)) {
            return getValueSlow(rows, l);
        }
        int dataType = rows.getColumnType(0);
        if (dataType == Value.NULL) {
            return ValueBoolean.get(false);
        }
        l = l.convertTo(dataType);
        if (rows.containsDistinct(new Value[] { l })) {
            return ValueBoolean.get(true);
        }
        if (rows.containsDistinct(new Value[] { ValueNull.INSTANCE })) {
            return ValueNull.INSTANCE;
        }
        return ValueBoolean.get(false);
    } finally {
        rows.close();
    }
}