Role of XE

[Seshaiah Chimata]

Hi,

Please advice what is the role of XE from the following line of code.

Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "SYSTEM", "manager");

I found the following entry in tnsnames.ora file

XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = Harikrishna-PC)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
    )
  )

I am able to execute the program. My question is, Are these related ?

Also, I changed the above 2 entries as given below

Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE19", "SYSTEM", "manager");

XE19 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = Harikrishna-PC)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE24)
    )
  )

I am getting following error
java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
The Connection descriptor used by the client was:
localhost:1521:xe24

Please advice

Thanks,
Seshu

[Ulf Dittmer]

Hmm, the first example uses "XE" in 3 places. The second one uses "XE19" in two places, "XE24" in one place, and then causes an error message. It seems kind of obvious what should be tried to fix the error, no?

[Seshaiah Chimata]

Even if I mess up with tnsnames.ora file and use this snipped in my code, It works fine

Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "SYSTEM", "manager");

I want to know the relationship between my program and tnsnames.ora file.

[Martin Vajsar]

Seshaiah Chimata wrote:I want to know the relationship between my program and tnsnames.ora file.

There isn't any. The connect string you're using does not use TNSNAMES.

Our Oracle FAQ contains a link to a page explaining connection strings. A connection string that would utilize TNSNAMES looks different from what you have.

[Seshaiah Chimata]

Thank you Martin, I am clear with connection string usage but not sure how to use/leverage tnsnames.ora file. Can you please provide an example how connection string can utilize tnsnames.ora file

[William P O'Sullivan]

It's been a while, but I believe tnsnames.ora is only used when you are using the "thick" oracle client.

WP

[Martin Vajsar]

I'm probably at risk of sounding repetitive, but our Oracle FAQ contains a link to a page explaining connection strings, in as much detail as necessary.

The description includes how to form a connection string which uses tnsnames.ora and also mentions that since version 10.2.0.1.0 even the thin driver does support using tnsnames.ora.

It is exactly two clicks away from here. Please ShowSomeEffort.