The query language of ejb3 is similar to the intermediate and Object-Oriented Query Language of SQL. It can be compiled into SQL statements that are acceptable to different underlying databases, thus shielding the differences between different
Case has two formats. Simple case function and case search function.--Simple Case function Case Sex When ' 1 ' Then ' men ' When ' 2 ' then ' women ' Else ' other ' END --case search function case If sex = ' 1 ' Then ' man ' When sex = ' 2 '
Address: http://www.ibm.com/developerworks/cn/rational/r-usecase-atm/index.html
Level: elementary
Fu chunyi, technical sales manager of Rational China, software department of IBM China Co., Ltd.
November 01, 2004
Use Case is a method used to
Case modeling GuideFu chunyi, technical sales manager of rational China, software department of IBM China Co., Ltd.November 01, 2004Original URL: http://www-128.ibm.com/developerworks/cn/rational/r-usecase-atm/@
Use case is a method used to describe system requirements. The process of describing system requirements using use cases is case modeling. The use case method was first proposed by Dr. IVA jackboson and was later integrated into the UML
1.0 Introduction
The task of the Query planner is to find the best algorithm or to say "query plan" to complete an SQL statement. As early as SQLite version 3.8.0, the component of the query planner has been rewritten so that it can run faster and
Case has two formats. Simple case function and case search function.--Simple Case function Case Sex When ' 1 ' Then ' men ' When ' 2 ' then ' women ' Else ' other ' END --case search function case If sex = ' 1 ' Then ' man ' When sex = ' 2 '
In the previous article, we learned the basic data CURD method, but in more cases, due to the difference in business logic, CURD operations are often not that simple, especially under complicated business logic, this is also a shortcoming of the
Database system is the core of MIS, and online transaction processing (OLTP) and online analytical Processing (OLAP) based on database is one of the most important computer applications in banks, enterprises and government departments. From the
In the previous article we have mastered the basic data curd method, but in more cases, due to the differences in business logic, curd operations are often not so simple, especially complex business logic below, this is the ActiveRecord mode of
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