1, Index An index is a set of data pointers stored on disk associated with a single table. The main advantage is they greatly speed up select, update, and delete statements, as the query optimizer only has to search the index rather than the entire t…

An index is used to speed up searching in the database. By default, when you create this table, your data will be stored on disk and sorted by the "Id" primary key column. This default sort is called the "Clustered Index". Affects the…

PARTII: SQL Basics CHAPTER 4Creating a Simple Query 介绍一种怎样创建SQL语句的技术--"Request/Translation/CleanUp/SQL" The SELECT operation in SQL can be broken down into three smaller operations, which we will refer to as the SELECT statement,the SELECT expre…

The following are the most suggested Oracle Certifications for Oracle Application Developers in Forms and Reports and as you already know that Oracle Forms 12c also released, so it is going to be used in long run. Oracle Certified Professional, Oracl…

 SQL Server I/O Basics Chapter 1http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/sqlIObasics.mspx SQL Server I/O Basics Chapter 2http://www.microsoft.com/technet/prodtechnol/sql/2005/iobasics.mspxStorage Performance for SQL Serverhttp:/…

Reference: http://blogs.msdn.com/b/felixmar/archive/2011/02/14/partitioning-amp-archiving-tables-in-sql-server-part-1-the-basics.aspx Database partitioning is a feature available in SQL Server(version 2005 and Up) which lets you split a table among m…

Execute Native SQL Query You can execute native raw SQL query against the database using DBContext. You can execute the following types of queries: SQL query for entity types which returns particular types of entities SQL query for non-entity types w…

前言 其实有些新的特性在SQL Server早就已经出现过,但是若非系统的去学习数据库你会发现在实际项目中别人的SQL其实是比较复杂的,其实利用新的SQL Server语法会更加方便和简洁,从本节开始我们将讲述一些SQL Server中早已出现的新语法,简短的内容,深入的理解,Always to reivew the basics. 初探APPLY运算符 APPLY运算符是一个非常强大的表运算符,但是APPLY不是标准的,相对应的标准叫做LATERAL,但是此标准并未在SQL Server中实现…

前言 上一节我们简单讲述了表表达式的4种类型,这一系列我们来讲讲使用视图的限制,简短的内容,深入的理解,Always to review the basics. 避免在视图中使用ORDER BY 上一节我们也讲述了使用表表达式必须满足的3个要求,其中就有一个无法保证顺序,也就是说的ORDER BY的问题,我们还是重点看看在视图中的限制.在常规查询中对于排序我们是这样做的. USE AdventureWorks2012 GO SELECT * FROM Sales.SalesOrderDetail…

前言 从这一节开始我们开始进入表表达式章节的学习,Microsoft SQL Server支持4种类型的表表达式:派生表.公用表表达式(CTE).视图.内嵌表值函数(TVF).简短的内容,深入的理解,Always to review the basics. 表表达式 表表达式没有任何的物理实例化,在查询表表达式时它们是虚拟的,内部查询是非嵌套的,换句话说,外部查询和内部查询直接合并到一个底层对象的查询中,使用表表达式的好处通常与代码的逻辑方面有关,而与代码的性能无关-摘抄自SQL Server…