微型oracle學習使用—oracle XE（oracle express edition

Oracle 11g XE 是 Oracle 數據庫的免費版本，支持標准版的大部分功能，占用內存小，很不錯。值得推薦。11g XE 提供 Windows 和 Linux 版本。

做為免費的 Oracle 數據庫版本，XE 的限制是：

• 最大數據庫大小為 11 GB  
• 可使用的最大內存是 1G
• 一台機器上只能安裝一個 XE 實例
• XE 只能使用單 CPU，無法在多CPU上進行分布處理

下面介紹安裝過程：
首先下載 Oracle 11g XE 並解壓，解壓后的DISK1目錄中包含了 setup.exe 文件，雙擊啟動安裝程序，首先會顯示一個協議信息，點擊繼續安裝：

• 操作系統至少是 Windows XP  
• 當前操作用戶必須有管理員權限
• 當前機器尚未安裝 XE

選擇安裝目錄：

設置數據庫密碼：

前面幾步過后會顯示一個安裝概要信息，包含以下內容：

• 偵聽器端口: 1521  
• MTS 服務端口: 2030
• HTTP 偵聽端口: 8080

接下來看看 XE 在我們的系統中安裝了什么？

Windows服務：

服務詳細列表：

• OracleServiceXE
  This is the actual database engine.
• OracleXETNSListener
  This service is responsible for listening incoming connections and passing successful connections to the database engine. Note, that if this service is down, you won’t be able to connect to the database remotely. Existing connections won't be affected. 
• OracleJobSchedulerXE
  This service is used when external jobs are run. By default it is disabled. If you plan to run external jobs (such as executables, batches etc), modify the account the service uses to use proper, low-privileged credentials and start the service. 
• OracleXEClrAgent
  On Windows platforms Oracle offers CLR integration. Since a CLR operation is run using an extproc process, it’s normally done using a dedicated (single threaded)extproc for a single session. This may not be the optimal way to handle CLR calls. ClrAgent provides a multi-threaded mechanism so that a single extproc process may serve several CLR calls.
• OracleMTSRecoveryService
  This one is responsible of resolving in-doubt transactions when Oracle is participating in distributed transactions with Microsoft Transaction Server.

程序列表：

在開始菜單中，你會發現 Oracle 新安裝的程序：

這些程序包括：

• Start and Stop Database are used to control the OracleServiceXE service
• Backup and Restore Database are scripts for backing up or restoring the database data using rman
• Run SQL Command Line opens a console based SQL*Plus which can be used to execute SQL commands or to run scripts against the database
• Get Started opens a web site used for investigating
  • storage, the amount of disk space used by tablespaces or drill to segments
  • current sessions and basic information about the sessions such as client and application information and active SQL statement
  • parameters show current initialization parameter values.

一些附加的工具

SQL Developer 

這是一個圖形化的 SQL 編輯器，可用來執行 SQL 命令、查看結果集、創建各種數據庫對象等等。

SQL Developer Data Modeler 

這是一個數據庫建模工具。

ODP.NET, ODT and ODAC

ODP.NET (Oracle Data Provider for NET) is the Oracle supplied library to use in application development when Oracle connection is required. ODP.NET utilizes several Oracle specific features and because of this it’s much more powerful than for example OLEDB based connections.  

ODT (Oracle Developer Tools for Visual Studio) is a set of Visual studio add-ins for Visual Studio that help application development. These add-ins include functionality such as automatic code generation, tuning tools, PL/SQL editor, AQ designers etc. Unfortunately, ODT cannot be used with Express Editions of Visual Studio because of the limitations of the Express Edition. 

ODAC (Oracle Data Access Components) is a package which contains ODP.NET but also other connectivity libraries such as ODBC, OLEDB and tools like SQL*Plus. ODAC can be downloaded with or without ODT.