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Parameterized Queries

QQL supports parameterized queries: instead of hardcoding values in the query text, you define named placeholders and supply their values at call time via the params argument of executeQuery.

Benefits:

  • The query is compiled once and cached - subsequent calls with different parameter values reuse the compiled plan, which reduces overhead when the same query runs repeatedly.
  • Separating the query structure from its data values improves readability and prevents injection issues.

As placeholder, use any valid QQL identifier anywhere a scalar value is expected. The identifier must follow standard QQL naming rules.

Example​

Parameterized query example
select trade.price as 'price', trade.size as 'size' from "mystream"
array join entries[this is TradeEntry] as trade
where timestamp >= START_TS and timestamp <= END_TS
    and symbol in ($S1, $S2)
    and trade.size > MIN_SIZE

The placeholders (START_TS, END_TS, $S1, $S2, MIN_SIZE) are bound to concrete values when executeQuery is called.

Supported Parameter Types​

Type groupTypes
IntegerINT8, INT16, INT32, INT64
FloatFLOAT32, FLOAT64
StringVARCHAR

Code Examples​

try (DXTickDB db = TickDBFactory.openFromUrl("dxtick://localhost:8011", false)) {
    String query =
        "select trade.price as 'price', trade.size as 'size' from kraken " +
        "array join entries[this is TradeEntry] as trade " +
        "where timestamp >= START_TS and timestamp <= END_TS " +
        "and symbol in ($S1, $S2) " +
        "and trade.size > MIN_SIZE";

    Parameter[] parameters = {
        Parameter.INTEGER("START_TS", Instant.parse("2026-03-04T16:25:30.000Z").toEpochMilli()),
        Parameter.INTEGER("END_TS", Instant.parse("2026-03-04T16:30:00.000Z").toEpochMilli()),
        Parameter.VARCHAR("$S1", "BTC/EUR"),
        Parameter.VARCHAR("$S2", "DOGE/USDT"),
        Parameter.FLOAT("MIN_SIZE", 5.1),
    };

    try (InstrumentMessageSource cursor =
             db.executeQuery(query, new SelectionOptions(true, false), parameters)) {
        while (cursor.next()) {
            System.out.println(cursor.getMessage());
        }
    }
}