Oracle Database 12c: Oracle OEM express

Together with Oracle Database 12c, Oracle has introduced a new administration console named Oracle Enterprise Manager Express (Oracle OEM Express). This “light” version of Enterprise Manager Database Console – which is not supported in Oracle 12c anymore – is a management product built into Oracle Database 12c.

There is no installation or management required, the database creation with dbca enables OEM Express and gives you the URL connect string.
As there is no mid-tier or middleware components in OEM Express, the performance overhead with the database server is not important.
The URL connection is: http://db_hostname:port/em/

OEM Express: the features

OEM Express only features the basic administration pages of Enterprise Manager Cloud 12c:

Configuration:

• Initialization parameters
• Memory
• Database feature
• Database properties

Storage:

• Tablespace
• Undo
• Redo
• Archive log
• Control files

Performance hub:

• Real-time performance monitoring and tuning
• Historical performance and tuning
• SQL monitoring
• ADDM
• Active Session History (ASH) analytics
• Automatic SQL Tuning Advisor and SQL Tuning Advisor

Thus, OEM Express allows you to manage the basic features of an Oracle database: user security, database memory, and storage. You can also access real time performance charts.
OEM Express is easy to handle and the response times are very correct.
The database homepage looks like the Cloud 12c homepage with its performance, resource, and sql monitoring pages:

The storage page displays the main properties of the tablespaces and datafiles (free space, datafile, etc.):

The user page displays the different user properties (account status, creation date, expiration date, etc.):

The performance hub page shows a lot of useful information (memory, I/O, monitored SQL, ADDM):

Conclusion

OEM Express might be a good solution if you do not have 100 databases to administrate. In this last case, you should use Oracle Enterprise Manager Cloud Control 12c.
With OEM express, Oracle has replaced the old resource-consuming Oracle Enterprise Manager Database Console by a new, easy-to-handle, and nicely performing product.
One of the main advantages is that you do not need to install the product: OEM Express is built into the database, but the performance impact is really not important.