TAILIEUCHUNG - SQL PROGRAMMING STYLE- P31

SQL PROGRAMMING STYLE- P31:Im mot trying to teach you to program in SQL in this book. You might want to read that again. If that is what you wanted, there are better books. This ought to be the second book you buy, not the first. I assume that you already write SQL at some level and want to get better at it. If you want to learn SQL programming tricks, get a copy of my other book, SQL for Smarties (3rd edition, 2005). | Do Not Use Object-Oriented Design for an RDBMS 67 relationship. For them to appear CREATE TABLE and disappear DROP TABLE is like living in a world of magic where a whole new species of creatures are created by any user on the fly. Likewise there are no OIDs in SQL. GUIDs auto-numbering and all of those proprietary exposed physical locators will not work in the long run. I have watched people try to force OO models into SQL and it falls apart in about a year. Every typo becomes a new attribute or class queries that would have been so easy in a relational model are now multitable monster outer joins redundancy grows at an exponential rate constraints are virtually impossible to write so you can kiss data integrity goodbye and so on. In a thread discussing OO versus relational modeling entitled impedance mismatch in the newsgroup in October 2004 one experienced programmer reported I m here to tell you what you already know you are 100 percent correct. I am stuck with working with an OO schema superimposed on an RDBMS. The amount of gymnastics that I need to go through to do what should be the simplest query is unimaginable. It took six man-hours me and one of the OO developers for three hours to come up with a query that was the equivalent of SELECT FROM Field_Offices The data needed consisted of basic information name of the office location address manager and phone. The final query was almost a full page long required the joining of all the various tables for each data element as each data element is now an object and each object has its own attributes so requires its own table and of course the monster object-linking tables so as to obtain the correct instance of each object. By the way which instance is the correct one Why the latest one of course unless it is marked as not being the one to use in which case look for the one that is so marked. And the marking indicator is not always the same value as there are several potential values. .

• Cơ sở dữ liệu
• cơ sở dữ liệu MySQL
• database SQL
• thiết kế CSDL quan hệ
• Kiến trúc hệ quản trị CSDL
• đặc tính cơ sở dữ liệu
• bảo mật cơ sở dữ liệu
• Cơ sở dữ liệu
• Hệ quản trị cơ sở dữ liệu MySQL
• Quản trị cơ sở dữ liệu
• Làm việc với MySQL
• Giới thiệu về MySQL
• Bài giảng Phần mềm nguồn mở
• Phần mềm nguồn mở
• Hệ quản trị cơ sở dữ liệu
• Lịch sử phát triển MySQL
• Kiến trúc MySQL
• MySQL Command Line
• MySQL Query Browser
• giáo trình cơ sở dữ liệu
• lý thuyết cơ sở dữ liệu
• bái giảng cơ sở dữ liệu
• tài liệu cơ sở dữ liệu
• Kết nối với MySQL
• Truy xuất cơ sở dữ liệu
• Quản lý dữ liệu
• Kết nối cơ sở dữ liệu
• Cập nhật dữ liệu
• Kích hoạt dữ liệu
• cơ sở dữ liệu sql server
• MySQL cơ bản