mysql - JDBC returns wrong number of affected rows

Question

If we have a table with 10 rows and we execute this query twice we get the wrong number of affected rows the second time.

Statement st = open();

st.executeUpdate("UPDATE  `tickets` SET price=1000"); // return 10
st.executeUpdate("UPDATE  `tickets` SET price=1000"); // return 10

Obviously it isn't correct because in first query the price of all rows is updated to 1000 and in the second query nothing actually changes but it returns 10 again!

How can I get the number of rows that are actually updated?

Answer 1

The JDBC specification apparently dictates that drivers have executeUpdate() return the number of rows found by the UPDATE statement, not the number of rows actually affected.

To have MySQL Connector/J return the number of rows actually changed you can add the property useAffectedRows=true to your connection URL, although the documentation does warn that it is

not JDBC-compliant, will break most applications that rely on "found" rows vs. "affected rows" for DML statements