java - JDBC Oracle 查询。使用 setInt() 而不是 setObject() 执行时速度慢

Question

我有以下代码片段:

    public static void main(String[] args) throws SQLException {
    Connection c = getConnection();
    long time = System.currentTimeMillis();
    PreparedStatement ps = c.prepareStatement(sqlQuery);
    int index = 1;
    for (String param: parameters) {
        if (isInt(param)) {
            //ps.setInt(index++, Integer.parseInt(param));
            ps.setObject(index++, Integer.parseInt(param), java.sql.Types.NUMERIC , 0);
        } else {
            ps.setString(index++, param);
        }
    }
    displayResult(ps.executeQuery());
    System.out.println("It took " + (System.currentTimeMillis()-time) + ".");

    time = System.currentTimeMillis();
    Statement s = c.createStatement();
    ResultSet rs = s.executeQuery(expandParametersInStatement(sqlQuery, parameters));
    displayResult(rs);
    System.out.println("It took " + (System.currentTimeMillis()-time) + ".");
}

使用 PreparedStatement 执行的查询比 Statement 方法慢 4000 倍。它们给出相同的结果，执行顺序没有太大区别。

使用 setObject() 而不是 setInt() 可以使 PreparedStatement 与 Statement 一样快。

有什么区别？数据库中的类型转换不会那么贵吗？数据库中的数据类型是 NUMBER(10)。我想这是使用的索引的问题。但是，我无法使用 CAST(x AS INTEGER) 在 SQL Developer 中复制它？

谢谢。

语句是:

private static String sqlQuery = "SELECT sum(value) " +
"FROM a monat, " +
"     n jahr, " +
"     kunde kunde " +
"WHERE monat.kunde_nr IN " +
"    (SELECT DISTINCT kunde.kunde_nr " +
"     FROM MASKE_4_KUNDEN kunde " +
"     WHERE kunde.firma_nr = ? " +
"       AND kunde.verkaufsbereich_nr = ? " +
"       AND kunde.vertriebsbereich_nr BETWEEN (CASE WHEN ? <> -1 THEN ? ELSE -9999999999 END) AND (CASE WHEN ? <> -1 THEN ? ELSE 9999999999 END) " +
"       AND kunde.vertreter_nr BETWEEN (CASE WHEN ? <> -1 THEN ? ELSE -9999999999 END) AND (CASE WHEN ? <> -1 THEN ? ELSE 9999999999 END)" +
"       AND kunde.konzern_nr BETWEEN (CASE WHEN ? <> -1 THEN ? ELSE -9999999999 END) AND (CASE WHEN ? <> -1 THEN ? ELSE 9999999999 END) " +
"       AND kunde.geschaeftsjahr = ? " +
"       AND kunde.kunde_nr BETWEEN (CASE WHEN ? <> -1 THEN ? ELSE -9999999999 END) AND (CASE WHEN ? <> -1 THEN ? ELSE 9999999999 END))" +
"  AND monat.firma_nr = ? " +
"  AND monat.verkaufsbereich_nr = ? " +
"  AND monat.jahr_nr = ? " +
"  AND jahr.kunde_nr = monat.kunde_nr " +
"  AND jahr.firma_nr = monat.firma_nr " +
"  AND jahr.jahr_nr = monat.jahr_nr " +
"  AND jahr.verkaufsbereich_nr = monat.verkaufsbereich_nr " +
"  AND kunde.kunde_nr = monat.kunde_nr " +
"  AND kunde.firma_nr = monat.firma_nr";

Answer 1

setInt() 方法接收 int 作为第二个参数(不是 Integer)。现在，我知道自动装箱应该有效，但显然它并不总是有效:http://www.coderanch.com/t/550628/JDBC/java/setInt-String-int-Lost我的猜测是它在旧版本的 JDBC 中不起作用，它在新版本中起作用但仍然存在问题......我会尝试使用 Integer.intValue() 看看它是否更好用!

如果有人对此有更多意见 - 我很乐意听到!