Step-BY-Step

摘要： http://plsql-tutorial.com/plsql-procedures.htmWhat is PL/SQL?PL/SQLstands for Procedural Language extension of SQL.PL/SQL is a combination of SQL along with the procedural features of programming languages.A Simple PL/SQL Block:Each PL/SQL program consists of SQL and PL/SQL statements which from a P 阅读全文

摘要： aterialized views are disk based and update periodically base upon the query definition.Views are virtual only and run the query definition each time they are accessed.Views evaluate the data in the tables underlying the view definition at the time the view is queried. It is a logical view of your t 阅读全文

摘要： Oracle的实体化视图提供了强大的功能，可以用在不同的环境中,实体化视图和表一样可以直接进行查询。实体化视图可以基于分区表，实体化视图本身也可以分区。主要用于预先计算并保存表连接或聚集等耗时较多的操作的结果，这样，在执行查询时，就可以避免进行这些耗时的操作，而从快速的得到结果。在数据仓库中，还经常使用查询重写（query rewrite）机制，这样不需要修改原有的查询语句，Oracle会自动选择合适的实体化视图进行查询，完全对应用透明。实体化视图和表一样可以直接进行查询。实体化视图还用于复制、移动计算,远程同步等方面。实体化视图有很多方面和索引很相似：使用实体化视图的目的是为了提高查询性能； 阅读全文

摘要： Question: I added an index hint in my query, but the hint is being ignored. What is the correct syntax for an index hint and how do I force the index hint to be used in my query?Answer:Oracle index hint syntax is tricky because of the index hint syntax is incorrect it is treated as a comment and not 阅读全文

摘要： Question:I have a SQL with multiple columns in my where clause. I know that Oracle can only choose one index, and I know about multi-column composite indexes, but I do not know how to determine the optimal column order for a composite index with multiple column values. What is the secret for creatin 阅读全文