Java SQL, General error org.hsqldb.HsqlException

Question

I'm working on Java and use Access (SQL) database. I want to insert into a table as you can see:

ResultSet resultSet = statement.executeQuery("INSERT INTO Mybooks (category,book_id) VALUES ('" + variable  + "'," + 64) + ")");

However, a strange error comes:

Caused by: org.hsqldb.HsqlException: General error

Answer 1

Use executeUpdate for database write operations

PreparedStatement insertStatement = con.prepareStatement("INSERT INTO Mybooks (category,book_id) VALUES (?, ?)"); // no SQL injection here!
insertStatement.setString(1, variable);
insertStatement.setInt(2, 64);
insertStatement.executeUpdate();