JDBC FAQ Part10

20: What is ment by ResultSet and What are the types of ResultSets are available in JDBC application?

            In jdbc applications ResultSets could be classified in the following two ways.

• On the basis of ResultSet privilizations (Concurancy):- 

There are 2 types of ResultSets.

• Read only ResultSet
• Updatable ResultSet

Read only ResultSet:-   It is a ResultSet, which will allow the users to read the        data only. To refer this ResultSet, we will use the following constant from ResultSet interface.

                        public static final int CONCUR_READ_ONLY;

 Updatable ResultSet:-  If is a ResultSet object, which will allow users to perform some updations on its content. To refer this ResultSet we will use the following constant from ResultSet interface.

                        public static final int CONCUR_UPDATABLE;

2)On the  basis of  the ResultSet cursor movement:-

There are 2 types of ResultSets.

• Forward  only ResultSet
• Scrollable ResultSet

Forward only ResultSet:-  It is a ResultSet object, which will allow the users to iterate the data in any forward direction. To refer this ResultSet object we will use the following  constant from ResultSet interface.

                        public static final int TYPE_FORWARD_ONLY;

Scrollable ResultSet:-  These are the ResultSet objects, which will allow the users to iterate the data in both forward and backward directions.
            There are 2 types of Scrollable ResultSets.

• Scroll sensitive ResultSets
• Scroll in sensitive ResultSets.

21:  What is the difference between ScrollSensitive ResultSet  and ScrollInsensitive  ResultSets?

Ans:  Scroll sensitive ResultSet is a ResultSet object, which will allow the later updations from database automatically after creating it. To refer this ResultSet we will use the following constant.
            public static final int TYPE_SCROLL_SENSITIVE;

            Scroll insensitive ResultSet is a ResultSet object, which will not allow later updations from database after creating it. To refer this ResultSet we will use the following constant from ResultSet interface.

• public static final int TYPE_SCROLL_INSENSITIVE;

22:What is the default ResultSet type in JDBC application and How it is possible to create a specific type of ResultSet object?

• The default ResultSet type in the jdbc applications is Read only and forward only.
• In jdbc applications we are able to specify the following types of the ResultSet combination to any particular ResultSet.

• read-only, forward only
• read-only, scroll sensitive
• read-only, scroll insensitive
• updatable, forward only
• updatable, scroll sensitive
• updatable, scroll insensitive

• if we want to specity a particular type to the ResultSet object then we should use either of the above constants combination as a parameter to createStatement() method, for this we will use the following method.

public Statement createStatement(int forward / ScrollSensitive / ScrollInsensitive, int  readonly / updatable)

Eg: Statement st = con. createSensitive(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
ResultSet rs = con.executeQuery(….);