IN predicate in PreparedStatement?

Question

How would you represent this using a PreparedStatement
DELETE FROM table WHERE id IN (....)
(.... is a list of integers that could be the id value)
Is it possible to assign a list of values using a single PreparedStatement '?'

Answer 1

The "in" version is, unsurprisingly, significantly faster for many items, since it doesn't have to do many network round trips to the database server.
With 100 items to delete, the program below shows the "in" version to be of the order of 30 times faster than 100 separate deletes. Your mileage will vary. E.g. if you delete using a non-indexed key from a table with a large number of rows, the full table scans will swamp the difference in network latency.
The significance of these differences will vary. If you do 10 deletes once in a blue moon, you won't care whether it takes 20 ms or 2 ms. But if you do that from e.g. a servlet in a busy web site, you will definitely care about SQL query latency.
Sample timings on an Oracle database:
with separate deletes: 297 ms
with separate deletes: 171 ms
with separate deletes: 174 ms
with separate deletes: 177 ms
with separate deletes: 212 ms
with separate deletes: 144 ms
with separate deletes: 153 ms
with separate deletes: 159 ms
with separate deletes: 131 ms
with separate deletes: 348 ms
with in statement: 6 ms
with in statement: 6 ms
with in statement: 12 ms
with in statement: 19 ms
with in statement: 5 ms
with in statement: 20 ms
with in statement: 4 ms
with in statement: 4 ms
with in statement: 4 ms
with in statement: 12 ms
import java.sql.*;
public class t
    public static void main(String args[])
        throws Exception
        DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
        Connection connection = DriverManager.getConnection(args[0], args[1], args[2]);
        int delete_set_size = 100;
        PreparedStatement stmt = connection.prepareStatement("delete from sja where a = ?");
        for (int n = 0; n < 10; n++) {
            long start = System.currentTimeMillis();
            for (int m = 0; m < delete_set_size; m++) {
                stmt.setInt(1, m);
                stmt.executeUpdate();
            long end = System.currentTimeMillis();
            System.out.println("with separate deletes: " + (end - start) + " ms");
        stmt.close();
        for (int n = 0; n < 10; n++) {
            long start = System.currentTimeMillis();
            StringBuffer buf = new StringBuffer();
            buf.append("delete from sja where a in (");
            for (int m = 0; m < delete_set_size; m++) {
                if (m != 0)
                    buf.append(',');
                buf.append(m);
            buf.append(')');
            stmt = connection.prepareStatement(buf.toString());
            stmt.executeUpdate();
            stmt.close();
            long end = System.currentTimeMillis();
            System.out.println("with in statement: " + (end - start) + " ms");