Project Management Porn
Anecdotally, I had always known that Software Engineers are terrible at estimation. I had never realised exactly how bad we are.
Some rules of thumb which seem to pop up now and again, is to take your engineers best estimates, and double them. Then you’re actually in the ball park.
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Extensible Markup Languages (XML) history begins with the development of Standardised Generalised Markup Language (SGML) by Charles Goldfarb, along with Ed Mosher and Ray Lorie in the 1970s while working at IBM (Anderson, 2004). SGML despite the name is not a mark-up language in it’s own right, but is a language used to specify mark-up languages. The purpose of SGML was to create vocabularies which could be used to mark up documents with structural tags. It was imagined at the time, that certain machine readable documents should remain machine readable for perhaps decades.
I was on the edge of writing some unkind things about JPox and Spring this week, as I dealt with the frustration of getting Spring to manage transactions for the JPox persistence code I was writing.
The issue I was dealing with, was the persistence of a org.springframework.orm.jdo.JdoUsageException. I decided to simplify, and I downloaded the JPox JDO Tutorial, and decided to reimplement it using Spring.
Read on for the cause, and solution to my problem. Continue reading
This paper evaluates and compares some of the possible storage devices and technologies that can be utilized for database storage. We distinguish the benefits of each type, and assess the best possible use for each. Continue reading
History of SQL
In 1970 Dr. E. F. Codd published his paper,“A Relational Model of Data for Large Shared Data Banks”. This became the foundation for the relation database system. This paper described a new way to structure data within a database, and led to the relational database systems we use today. Continue reading
Data Warehousing
Information systems must support the day to day business, as well as the long term, strategic goals of an organisation. The problems for most businesses is that supporting day to day business operations and supporting long term strategic planning require different sets of data and tools.
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Object Features
SQL-1999 introduced object support into the SQL standard. The SQL-1999 standard had to be backward compatible with the existing SQL-1992 standard, so object support was implemented as an extension to the existing standard. The types defined by SQL-1992 were retained, and the standard modified to support user defined types (UDT) with object-like features.
Portable SQL
Portability is a very desirable feature in any application which stores information in a database. A software developer would like to use a small in-memory database while developing an application, such as Apache Derby, but deploy the finished application to an Oracle database to make use of it’s scalability and high availability features. In order to do this, both database systems need a certain amount of commonality which the application can use.
ODBC stands for Open DataBase Connectivity. It is a database middleware application which allows an application access data from a database.
What is ANSI?
ANSI is the American National Standards Institute and is a non-profit organisation which oversees the development of standards for products, services, processes, systems and personnel in the US. ANSI also coordinates US standards with international standards bodies, so that US products can be used worldwide.
