Oracle Enterprise Manager Database Express 12c Overview

Oracle Database 12c introduced Oracle Enterprise Manager Database Express 12c.

Oracle Enterprise Manager Express is a Web-based interface for managing an Oracle database.

Using Oracle EM Database Express, you can perform basic administrative tasks such as user, performance, memory, and space management.

Oracle Enterprise Manager Database Control is no longer available.

EM Database Express is only available when the database is open.

It provides administration function for both single instance database and cluster database.

It cannot be used to startup/shutdown the database.

It cannot be used to change the archivelog mode.

It cannot be used to backup or recover the database.

Following is the home page of the EM Express , note that it has the same look and feel of the Oracle Enterprise Manager:

Following are the top-level menus and the available functionality:

Configuring the HTTP Port

You can access Enterprise Manager Database Express using the URL that was displayed during installation. The default port used is 5500. In case you want to use a different port, you need to configure the port using the dynamic protocol registration
method. After the HTTP port is configured, you use it to access Enterprise Manager Express. In the following example, we will configure Enterprise Manager Database Express to run on port 8080:

Verify that the listener is started by executing the lsnrctl status command:

Log in to SQL*Plus as the SYSDBA user and verify that the DISPATCHERS parameter in the initialization parameter file includes the PROTOCOL=TCP attribute:

To know the current port for Enterprise Manager Express:

To set a different port:

sqlplus / as sysdba
exec dbms_xdb_config.sethttpport(8080);

Accessing the EM Express:

The Database Home page is the main database management page in Enterprise Manager Database Express. To access the Database Home page, perform the following steps:

In your Web browser enter the URL to access Enterprise Manager: http://database-hostname:portnumber/em. In this case, since the database is installed in the local machine, localhost is used for database-hostname.

In our example, use the following URL to access the EM database express:

https://db01:5500/em

Log in to Enterprise Manager Database Express with an authorized user account such as SYSTEM. Enter the username and password in the appropriate fields. Click Login.

The Database Home page is displayed:

Configuring EM express for PDBs:

alter session set container=pdb1;
exec dbms_xdb_config.sethttpsport(5511);
select dbms_xdb_config.gethttpsport from dual;
https://db01:5511/em

Some Remarks:

• When you connect with EM Express to a CDB/root container, the submenu Storage==> Tablespaces will not appear
• Also, if you tried to create a common user, the “Default Tablespace” & “Default Temporary Tablespace” List-Of-value “LOV” will be empty, although you may continue and he will create the user with the default tablespace as “SYSTEM”
• Also, in this case , if you created a tablespace from sqlplus, you will not be able to see it when creating a user, you find that the T.Ss LOV is empty.
• So, the only way to create the user with non-default TSs is to create it from sqlplus and you can see it from Express after that.
• When you connect with the EM Express to a PDB, all menus will be there.
• If you create a common user from sqlplus and assigned it a default tablespace that exists only in the root container, this tablespace will be created automatically in all PDBs, even if the PDB is mounted !

So, for tablespaces LOV to be populated when you create a new user in the DATABSE Express:

1- All PDBs must be open
2- You will get only the common tablespaces (SYSTEM,SYSAUX,USERS,TEMP) that exist in all containers.
3- If you want to get another user-defined tablespace, then you have to create it first in all containers from sqlplus, before creating the user from the database express.

Following are the requirements to create a common user in general:

• You must be connected with a common user with the CREATE USER privilege.
  The current container must be the root container.
• The username for the common user must be prefixed with “C##” or “c##” and contain only ASCII or EBCDIC characters.
• The username must be unique across all containers.
• The DEFAULT TABLESPACE, TEMPORARY TABLESPACE, QUOTA and PROFILE must all reference objects that exist in all containers.
• You can either specify the CONTAINER=ALL clause, or omit it, as this is the default setting when the current container is the root.

How to know if you are login to CDB or PDB from the login screen?

If you are connected to a CDB , the login screen will contain a field called “Container Name”, while this field is not there when you are connected to a PDB.

Thanks
Ahmed