A DATABASE MODEL or DATABASE SCHEMA is the structure or format of a database(It is a structured collection of records or data that is stored on a server), described in a formal language supported by the DATABASE MANAGEMENT SYSTEM(Software to manage databases). Schemas are generally stored in a data dictionary(centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format).A data model is not just a way of structuring data: it also defines a set of operations that can be performed on the data.
MODELS
FILE MODEL The flat (or table) model consists of a single, two-dimensional array of data elements, where all members of a given column are assumed to be similar values, and all members of a row are assumed to be related to one another.
HIERARCHY MODEL
Data is organized into a tree-like structure, implying a single upward link in each record to describe the nesting, and a sort field to keep the records in a particular order in each same-level list. Hierarchical structures were widely used in the structure of XML documents. This structure allows one 1:N relationship between two types of data. This structure is very efficient to describe many relationships in the real world; recipes, table of contents.One limitation of the hierarchical model is its inability to efficiently represent redundancy in data.Parent–child relationship: Child may only have one parent but a parent can have multiple children. Parents and children are tied together by links called "pointers“.
NETWORK MODEL
It organizes data using two fundamental constructs, called records and sets.Records contain fields and Sets define one-to-many relationships between records.A record may be an owner in any number of sets, and a member in any number of sets.Parent–child relationship: Child can have more than one parent and a parent can also have multiple children.
I am big freak to attend summit. Recently I attended ADOBE RIA SUMMIT at Bangalore and Before that FOSS.in all these places are great as people share there vast knowledge in small amount of time. This places actually tell you where to start and where the future is up to.I am waiting sum one would sponsor me
Above summit is god of all. I wish it happens in bangalore. This is the best summit i heared foe web site designing.Please leave the posts about how the conference was if anyone has attended.
Well i got an error in mysql for which i banged my head for full 2 days and figured out it was a small change(I knw every bugs ends the ame way.. :)).Well , i didnt find any forum that explains about the bug and its solution.
Query: Select * from where tot = tot1 BUG: Unknown column "tot1" in where clause.
SOLUTION: Select * from where tot = 'tot1'
If the value of the tot1 is TOT it works fine if it is any thing other than that it gives an error. I could never figure why it acts so weird, Well if any1 knows the solution lets me know and simple image has been attached for the results.
Just imagine using i-phone instead of laptop. Things would be more simpler!!!! So for those outraged with the Windows XP "running" on a "slow" processor like iPhone's, I say - you can all relax, the actual processing was done on a back-end virtual desktop and remotely delivered via Citrix XenDesktop.
One bad thing about web is you read about one version which took more than years of time by more than a million researchers... in a mins time you come to see web 3.0.Well we will talk about WEB 3.0 in next post but for now just 2.0
Web 2.0 is a base on the web 1.0 with the same networking techniques giving more enhancements to the user interaction with the net. Web 2.0 sites often feature a rich, user-friendly interface based on below tags. Any internet applications made using the concept of web 2.0 are called RIA.
Rich internet applications techniques such as AJAX, Adobe Flash, Flex, JavaFX, Curl and Silverlight have evolved that have the potential to improve the user-experience in browser-based applications. Specialized protocols such as FOAF and XFN (I have never gone through this protocols, but I have given links below.) extend the functionality of sites or permit end-users to interact without centralized websites.
ADOBE AIR: I was in air at ninth cloud when i read about this.Dont miss the e-bay application.Its amazing.Best part of it is the response facts are similar to javascript and very fast than cache implementation.These applications are created as on-line application but there basic uses are for desktop deployment.
ADOBE FLEX: FLEX in simple wrds HTML + FLASH. being from the networking back ground I was not very much impressed with this outcome as it turns a web application very heavy n slow to handle but advantageous is the look-n-feel u get from this, it make's the user crazy about the site.Check out lee burner site. You will stick to that site more than a day..It’s an SDK to develop WEB2.0 with all the rich contexts. In context of web1.0 he can match html as flex pages and java script which dynamic content as coldfusion ability from ADOBE
http://en.wikipedia.org/wiki/Adobe_Flex
MICROSOFT SILVER LIGHT: This not a framework rather it’s a browser plugin.Its just a sibling of Adobe flash with more good performance techniques. Worst part of it is it does not support any OS based browsers especially safari and other Linux based browsers. So it is also called browser-unsafe plug-in.
It is a RIA frame work with similar to flex but performance was its very good than flex as they should be accessible by mobile applications that is using JAVAME.
If anyone wants to know internal content of any above applications .This site below is very good and informative
There are few more like CURL, open lazzalo..You may think who is she to give her comments.Well these are just my comments.Do drop in your comments in the comments column.
