Transaction Isolation - Part 1

SQL 2005 is a relational database model and multiple users can access the data sitting in the server box. Let us think there is an organization conducting a survey by taking help from their employees. Lat us say that the cumulative outcome of their reply is updated in a single row. Now, when two employees (The client application they use for the survey) try to update the same row does sql server discard an update from one person?

 

Let us take one more example. There is big stock exchange system and a client web application is retrieving a row as an enquiry of knowing how a particular business stands in the stock market. But let us again assume when a row is read; an update is half a way. Now the situation leads some columns of the row has older values and some columns has the updated values.

 

SQL Server tackles the above situation by using the Transaction Isolation