Problem with Oracle SQL Developer

by toni

could not make database connection ... Pleas for Help

could not make database connection ... Pleas for Help

Assuming you have successfully installed an Oracle database or have one available to use the there are several pieces of information you need and several things you can check.

For a basic connection from SQL Developer to the Oracle database you need to know either the database SID or service name, the name of the machine/system/node where the database has been installed and obviously the username and password of an active account.

If you are using the TNS connection type then all you need is the database alias as defined in the tnsnames.ora file found in the network/admin directory on your system. However if you can't make a connection then you still need to check the connection using other methods.

So what do you check?
  1. start by checking the database is up - use sql*plus on the machine where the database was installed and enter a valid username and password. If this is successful the database is up. If not (assuming that the username and password are correct) start the database. If you don't have console access to the server, check with your dba that the database is up.
  2. step 2 - from the system command prompt (i.e run cmd.exe if you're using Windows or get a terminal session of you're on Linux/UNIX) enter ping <hostname> where <hostname> is the name of the machine where the database has been installed. If the database is installed locally then this will be "localhost" (without the quotes), otherwise the dba will give you this information. If this is successful (see "using ping") proceed to step 3. If unsuccessful check the host name and the spelling. Unless you can establish a basic network connection to the database server you can't go any further
  3. step 3 is to check the Oracle networking layer. From the command line (as per step 2) enter tnsping <database name> where <database name> is the sid or service name, or database alias on the client. That should respond with all the database details (see "Using TNSPING"). If not, check the spelling of the database name/alias/sid. Unless you can ping the database you can't go any further.
  4. step 4 - run sql*plus on your client machine (where sqldeveloper is installed) and attempt to login with the username and password. If that is unsuccessful then check that the account is active and that the username and password are correct. N.B. since Oracle 11g the password is case sensitive
  5. step 5 - you know that the database is up, and that you can connect to it so all you need to is enter the connection details into the appropriate fields in SQL Developer.

See also oracle-xe-database-connection-test-status-failure-test-failed-io-error-the-network-adapter-could-not-establish-the-connection.html if you're using Oracle XE.

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