When is ResultSet Needed

0
votes

Which SQL statement needs a ResultSet to process return data? Update, Select, Insert, Delete? In JDBC

1
sqljdbc
Only selects return data. - Shadow
SET (assignment), CALL with output data. - jarlh
Quite simple: any statement for which executeQuery() will succeed and not throw an exception. It is usually select, but database system also have other statements or constructs that return a result set (this varies per database system). - Mark Rotteveel

1 Answers

0
votes

A ResultSet represents the database result set of a query. See https://docs.oracle.com/javase/8/docs/api/java/sql/ResultSet.html

Here is an example:

Statement statement = connection.createStatement();
String sql = "select * from users";
ResultSet result = statement.executeQuery(sql);

You can use the ResultSet to get the data from the table

 while(result.next()) {
     String name = result.getString("name");
     System.out.println(name);
}

...or to update an entry

result.absolute(5); // moves the cursor to the fifth row of rs
result.updateString("name", "Cthullhu");
result.updateRow();

After use, you should close the ResultSet and the Statement

result.close();
statement.close();

You use a ResultSet after a select query using execute on the statement.

If you have update, insert or delete you can use executeUpdate on the statement

See this introduction from Oracle: https://docs.oracle.com/javase/tutorial/jdbc/basics/processingsqlstatements.html#creating_statements