这个链接：Newbie Guide to Oracle 11g Database Common Problems应该帮助你，如果你遇到一些常见的问题，创建您的数据库。

最好的运气！

编辑：当你使用XE，你应该有一个已经创建的数据库，使用sql * Plus和sql Developer等连接，信息在这里：Connecting to Oracle Database Express Edition and Exploring It。

提取：

Connecting to Oracle Database XE from sql Developer sql Developer is a
client program with which you can access Oracle Database XE. With
Oracle Database XE 11g Release 2 (11.2),you must use sql Developer
version 3.0. This section assumes that sql Developer is installed on
your system,and shows how to start it and connect to Oracle Database
XE. If sql Developer is not installed on your system,see Oracle
Database sql Developer User’s Guide for installation instructions.

Note:

For the following procedure: The first time you start sql Developer
on your system,you must provide the full path to java.exe in step 1.

For step 4,you need a user name and password.

For step 6,you need a host name and port.

To connect to Oracle Database XE from sql Developer:

Start sql Developer.

For instructions,see Oracle Database sql Developer User’s Guide.

If this is the first time you have started sql Developer on your
system,you are prompted to enter the full path to java.exe (for
example,C:\jdk1.5.0\bin\java.exe). Either type the full path after
the prompt or browse to it,and then press the key Enter.

The Oracle sql Developer window opens.

In the navigation frame of the window,click Connections.

The Connections pane appears.

In the Connections pane,click the icon New Connection.

The New/Select Database Connection window opens.

In the New/Select Database Connection window,type the appropriate
values in the fields Connection Name,Username,and Password.

For security,the password characters that you type appear as
asterisks.

Near the Password field is the check Box Save Password. By default,it
is deselected. Oracle recommends accepting the default.

In the New/Select Database Connection window,click the tab Oracle.

The Oracle pane appears.

In the Oracle pane:

For Connection Type,accept the default (Basic).

For Role,accept the default.

In the fields Hostname and Port,either accept the defaults or type
the appropriate values.

Select the option SID.

In the SID field,type accept the default (xe).

In the New/Select Database Connection window,click the button Test.

The connection is tested. If the connection succeeds,the Status
indicator changes from blank to Success.

Description of the illustration success.gif

If the test succeeded,click the button Connect.

The New/Select Database Connection window closes. The Connections pane
shows the connection whose name you entered in the Connection Name
field in step 4.

You are in the sql Developer environment.

To exit sql Developer,select Exit from the File menu.