simple insert operation

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simple insert operation

Aydın Toprak
Hii guys,

I am very newbie about postgresql and I am making practice,
however I couldnt been able to insert a simple item to my DB via jdbc...


here is my code  for insertion...

        Class.forName("org.postgresql.Driver");
        String connectionStr = "jdbc:postgresql://localhost:5432/XXXX";
        Connection connection =
java.sql.DriverManager.getConnection(connectionStr, "XXXX", "XXXX");
        String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
(3, 5)";
        PreparedStatement query = connection.prepareStatement(sqlQuery);
        query.executeUpdate();
        connection.close();

but I cant compile it

the errors

-------------------------------------------------------------------------------------------
form.java:26: unreported exception java.lang.ClassNotFoundException;
must be cau
ght or declared to be thrown
                Class.forName("org.postgresql.Driver");
                             ^
form.java:28: unreported exception java.sql.SQLException; must be caught
or decl
ared to be thrown
                Connection connection =
java.sql.DriverManager.getConnection(con
nectionStr, "XXXX", "XXXX");
                                                                           
^
form.java:30: unreported exception java.sql.SQLException; must be caught
or decl
ared to be thrown
                PreparedStatement query =
connection.prepareStatement(sqlQuery);

                                                                     ^
form.java:31: unreported exception java.sql.SQLException; must be caught
or decl
ared to be thrown
                query.executeUpdate();
                                   ^
form.java:32: unreported exception java.sql.SQLException; must be caught
or decl
ared to be thrown
                connection.close();
                                ^
5 errors
-------------------------------------------------------------------------------------------

what is the problem I am stuck with it..





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Re: simple insert operation

Csaba Nagy
Aydin,

You're obviously beginner at Java too :-)

The problem has nothing to do with JDBC, you must catch the Java
exceptions which are declared to be thrown by the methods you use (the
compilation error message is quite explicit about which ones), or
declare them to be thrown by your code. Look up some Java tutorial,
and/or use an intelligent IDE which highlights you the errors and
possibly fixes them too automatically... IntelliJ is a good one (not
free).

Other than that, from a superficial check, I guess your code is Ok.

Cheers,
Csaba.

On Thu, 2005-09-08 at 09:58, Aydın Toprak wrote:

> Hii guys,
>
> I am very newbie about postgresql and I am making practice,
> however I couldnt been able to insert a simple item to my DB via jdbc...
>
>
> here is my code  for insertion...
>
>         Class.forName("org.postgresql.Driver");
>         String connectionStr = "jdbc:postgresql://localhost:5432/XXXX";
>         Connection connection =
> java.sql.DriverManager.getConnection(connectionStr, "XXXX", "XXXX");
>         String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
> (3, 5)";
>         PreparedStatement query = connection.prepareStatement(sqlQuery);
>         query.executeUpdate();
>         connection.close();
>
> but I cant compile it
>
> the errors
>
> -------------------------------------------------------------------------------------------
> form.java:26: unreported exception java.lang.ClassNotFoundException;
> must be cau
> ght or declared to be thrown
>                 Class.forName("org.postgresql.Driver");
>                              ^
> form.java:28: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 Connection connection =
> java.sql.DriverManager.getConnection(con
> nectionStr, "XXXX", "XXXX");
>                                                                            
> ^
> form.java:30: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 PreparedStatement query =
> connection.prepareStatement(sqlQuery);
>
>                                                                      ^
> form.java:31: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 query.executeUpdate();
>                                    ^
> form.java:32: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 connection.close();
>                                 ^
> 5 errors
> -------------------------------------------------------------------------------------------
>
> what is the problem I am stuck with it..
>
>
>
>
>
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> TIP 3: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faq


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Re: simple insert operation

Roland Walter
In reply to this post by Aydın Toprak
Aydın Toprak schrieb:

> Hii guys,
>
> I am very newbie about postgresql and I am making practice,
> however I couldnt been able to insert a simple item to my DB via jdbc...
>
>
> here is my code  for insertion...
>
>        Class.forName("org.postgresql.Driver");
>        String connectionStr = "jdbc:postgresql://localhost:5432/XXXX";
>        Connection connection =
> java.sql.DriverManager.getConnection(connectionStr, "XXXX", "XXXX");
>        String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
> (3, 5)";
>        PreparedStatement query = connection.prepareStatement(sqlQuery);
>        query.executeUpdate();
>        connection.close();
>
> but I cant compile it
>
> the errors
>
> -------------------------------------------------------------------------------------------
>
> form.java:26: unreported exception java.lang.ClassNotFoundException;
> must be cau
> ght or declared to be thrown
>                Class.forName("org.postgresql.Driver");
>                             ^
> form.java:28: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                Connection connection =
> java.sql.DriverManager.getConnection(con
> nectionStr, "XXXX", "XXXX");
>                                                                            
> ^
> form.java:30: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                PreparedStatement query =
> connection.prepareStatement(sqlQuery);
>
>                                                                     ^
> form.java:31: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                query.executeUpdate();
>                                   ^
> form.java:32: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                connection.close();
>                                ^
> 5 errors
> -------------------------------------------------------------------------------------------
>
>
> what is the problem I am stuck with it..
>

The problem is, that all methods mentioned in the error messages
throw exceptions. Exceptions in java must be catched in try-catch-block

try {
        method();
        ...
} catch (ExceptionThrownByMethod e) {
    actOnExceptionOrNot();
        ...
       
}

You can omit the try-catch-block, if the method sorounding the called
method throws the exception:

void doCallMethod() throws ExceptionThrownByMethod {
        method();
        ...
}

But then you need to catch the Exception at the place where
doCallMethod() is called.

Look in a documentation for the java programming language for more
information.


--
Roland Walter                  phone: +49 (0) 22 25 / 88 2-41 1
MOSAIC SOFTWARE AG               fax: +49 (0) 22 25 / 88 2-20 1
Am Pannacker 3                mailto: rwa (at) mosaic-ag (dot) com
D-53340 Meckenheim              http://www.mosaic-ag.com

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Re: simple insert operation

Diego Gil
In reply to this post by Aydın Toprak
Hi,

The problem is that you never catch exceptions, specifically
SQLException. It is more a Java problem that a PostgreSQL problem. Maybe
you should read a little more about Java.

http://java.sun.com/docs/books/tutorial/essential/exceptions/index.html

Look at the modified code below.

Besides, it doesn't make sense to use PreparedStatement if don't use any
variable inside.

Regards,
Diego.

El jue, 08-09-2005 a las 10:58 +0300, Aydın Toprak escribió:
> Hii guys,
>
> I am very newbie about postgresql and I am making practice,
> however I couldnt been able to insert a simple item to my DB via jdbc...
>
>
> here is my code  for insertion...
>
try {
>         Class.forName("org.postgresql.Driver");
} catch (java.lang.ClassNotFoundException nfe) {
        nfe.printStackTrace();
}

try {
>         String connectionStr = "jdbc:postgresql://localhost:5432/XXXX";
>         Connection connection =
> java.sql.DriverManager.getConnection(connectionStr, "XXXX", "XXXX");
>         String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
> (3, 5)";
>         PreparedStatement query = connection.prepareStatement(sqlQuery);
>         query.executeUpdate();
>         connection.close();

} catch (java.sql.SQLException se) {
        se.printStackTrace();
}

>
> but I cant compile it
>
> the errors
>
> -------------------------------------------------------------------------------------------
> form.java:26: unreported exception java.lang.ClassNotFoundException;
> must be caught or declared to be thrown
>                 Class.forName("org.postgresql.Driver");
>                              ^
> form.java:28: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 Connection connection =
> java.sql.DriverManager.getConnection(con
> nectionStr, "XXXX", "XXXX");
>                                                                            
> ^
> form.java:30: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 PreparedStatement query =
> connection.prepareStatement(sqlQuery);
>
>                                                                      ^
> form.java:31: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 query.executeUpdate();
>                                    ^
> form.java:32: unreported exception java.sql.SQLException; must be caught
> or decl
> ared to be thrown
>                 connection.close();
>                                 ^
> 5 errors
> -------------------------------------------------------------------------------------------
>
> what is the problem I am stuck with it..
>
>
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faq
>
>


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Re: simple insert operation

Kevin Grittner
In reply to this post by Aydın Toprak
Hi Ayd*n,
 
Others have addressed your compile errors, but I see something which might cause you problems at run time.
 
Identifiers which are not "quoted" will be treated as lower case in PostgreSQL, so your query will try to access "passtable"."idcol" instead of "passTable"."idCol".  If you created the table without using quotes it will be in lower case and you will be OK referencing it without quotes no matter what capitalization you use; however, if the table really exists in your database with the camel case identifiers, you must use quotes.
 
-Kevin
 
 
>>> Ayd*n Toprak <[hidden email]> 09/08/05 2:58 AM >>>
 
        String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
(3, 5)";


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Re: simple insert operation

Aydın Toprak
In reply to this post by Aydın Toprak
I have faced & solved all the problems that you have  mantioned ..
try-catch statements and this "lowercase" situation.
the lowercase situation was the most annoying one...


Thanks for your  help...


Kevin Grittner wrote:

>Hi Ayd*n,
>
>Others have addressed your compile errors, but I see something which might cause you problems at run time.
>
>Identifiers which are not "quoted" will be treated as lower case in PostgreSQL, so your query will try to access "passtable"."idcol" instead of "passTable"."idCol".  If you created the table without using quotes it will be in lower case and you will be OK referencing it without quotes no matter what capitalization you use; however, if the table really exists in your database with the camel case identifiers, you must use quotes.
>
>-Kevin
>
>
>  
>
>>>>Ayd*n Toprak <[hidden email]> 09/08/05 2:58 AM >>>
>>>>        
>>>>
>
>        String sqlQuery = "INSERT INTO passTable (idCol , pass) VALUES
>(3, 5)";
>
>
>
>  
>


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