今天重新安装Delphi后，发现以前的程序不能编译，错误提示为：File not found: 'DBAccess.dcu'，这个'DBAccess.dcu'j是什么东西呢？ 在网上查了一下，也没有找到，后来在我以前的控件包里仔细找了一下，发现'DBAccess.dcu'原来是ODAC控件里的一个文件，ODAC是一个让Delphi连接Oracle的三方组件，安装以后就可以了，看一下ODAC官方介绍吧，英文的，将就看。
Oracle Data Access Components
Oracle Data Access Components (ODAC) is a library of components that provides native connectivity to Oracle from Delphi, Delphi for .NET, C++Builder and Kylix. The ODAC library is designed to help programmers develop faster and cleaner Oracle database applications. ODAC is a complete replacement for standard Oracle connectivity solutions and presents an efficient native alternative to the Borland Database Engine and dbExpress for access to Oracle.
If you use ODAC to connect to Oracle in Direct mode, you do not need to install Oracle client software on your machine or deploy any additional libraries with your ODAC-based application. The only requirement for using in Direct mode is having the TCP/IP protocol support in the Operating System. Detailed requirements for using ODAC in Client mode can be found in the Requirements topic in the ODAC Help documentation. Client mode is enabled by default.
Compiled versions of ODAC are installed automatically by the ODAC Installer for all supported IDEs except Kylix. Versions of ODAC with Source Code must be installed manually. For more information, see the Installation topic of the ODAC Help documentation.
It is important to know that ODAC, SDAC, MyDAC, and IBDAC components use the common base packages, so product compatibility is provided for the current build only. In the other words, if you upgrade one of the installed products, it may conflict with older builds of other products. In order to continue using the products simultaneously, you should upgrade all of them at the same time.
Documentation and informational resources
ODAC comes with full documentation, which includes a detailed reference for all the ODAC components and classes and set of articles that highlight ODAC advanced functionality. The ODAC documentation is integrated into your IDE at install time. It can be invoked from the Oracle menu added to the Menu Bar, or by pressing F1 in an object inspector or on a selected code segment.
If your problem is not covered in the documentation, FAQ, or forum, see the support page for information on how to contact the ODAC support team.