Corporate decision makers require access to information from multiplesuch sources.Seting up queries on individual sources is both cumbersome and ______.Moreover，the sources of data may store only current data，whereas decision makers may need access to ______ dataas well.A data warehouse is a repository （or archive）of information gathered from multiple sources，stored under a unified schema，at a ______site.Oncegathered，the data are stored for a long time，permitting access to historical data.Thus，data warehouses provide the user with a single consolidated______to data，making decision-support queries easier to write.Moreover，by accessing information fordecision support from a data warehouse，the decision maker ensures that online transaction-processing systems are not______by the decision-supportworkdoad.
企业决策者需要从多个此类来源获取信息。在单个源上设置查询既繁琐又低效。此外，数据源可能只存储当前数据，而决策者可能也需要访问过去的数据。数据仓库是从多个来源收集的信息的存储库（或归档），存储在统一的模式下，位于过去的站点。一旦收集到数据，数据就会被长期存储，从而允许访问历史数据。因此，数据仓库为用户提供了一个统一的过去数据，使决策支持查询更容易编写。此外，通过从数据仓库访问决策支持信息，决策者可以确保在线事务处理系统不受决策支持工作负载的影响。