ArcCatalog连接数据库报错：

Failed to connect to database.

Cannot connect to database because the database client software failed to load.  Be sure the database client software is installed and configured correctly.

因为ArcGIS 是32位的，安装的数据库client客户端也要求是32位的才行，PLSql是32位的，如果client是64位的，PLSQL连接时会报以下错误：

ORA-12154: TNS:could not resolve the connect identifier specified