Numerous Active Effects Set (MARS) are a different sort of element put-out with ADO.Net 2.0 that enables one to perform several questions otherwise stored measures on a single commitment. As a result, multiple submit-just, read-only effect sets. In the previous versions off ADO.Online, you can execute only one ask at the same time using a single partnership. Now, into regarding SQL Machine 2005 and you may ADO.Online dos.0, your quite easily can do multiple logical batches in one single commitment. This short article helps guide you to use MARS in an ASP.Web Web page. In addition talks about the latest affairs where MARS is suitable and also have abilities experts.
This is MARS
If you utilize DataReader on the apps, you currently have seen the feared error message: “There is certainly currently an unbarred DataReader of this so it Partnership hence must be signed first.” MARS enables you to prevent this content by allowing you to discover several SqlDataReader stuff on one union. MARS permits a loan application to own more than one SqlDataReader discover into a connection when per illustration of SqlDataReader was become away from a different sort of demand. Each SqlCommand target you devote contributes a supplementary course towards partnership.
Automagically, MARS can be acquired just on the is the very first SQL Servers type to support MARS. Automagically, MARS try permitted as soon as you utilize the categories on Program.Data.SqlClient namespace to connect to SQL Machine. not, in addition can be clearly control this particular aspect that with a phrase couple on the connection sequence. Including, you can clearly place new MultipleActiveResultSets trait from the commitment sequence to help you Correct the following:
- Carry out a good SqlConnection target and initialize it towards the compatible commitment sequence.
- Discover the connection by using the Discover types of new SqlConnection target.
- Perform individual SqlCommand things for the necessary details to perform the latest ask. While you are starting the newest SqlCommand things, remember to affiliate all of them with the latest in earlier times authored SqlConnection object.
- After you have created the SqlConnection target, then you can be invoke the newest ExecuteReader particular the latest SqlCommand target to perform new question.
- In the long run, close this new SqlConnection object by carrying out the Romantic approach.
MARS Execution
This new analogy this article gifts demonstrates how to make use of ple screens categories and product recommendations from the Northwind database. Each class your recover regarding the kinds desk, you then tend to inquire the items desk (for the classification ID since the a quarrel) to return all the products which belong because classification. You will learn how to pertain brand new for this condition.
Basic, create an alternate Web site entitled ed ple.aspx so you’re able to they. Now, modify the password regarding ple.aspx document to look like the pursuing the:
Take a closer look during the just what lines about significantly more than password do. Basic, the code retrieves the relationship string from the web.config file utilising the following range:
The above collection of code retrieves the partnership string about ConnectionStrings area of the websites.config file. The connection sequence try kept in the net.config as follows:
After that, the fresh new code initializes brand new categorySql and you may productsSql variables with the suitable SQL statements. Next, it will make an instance of brand new SqlConnection object through an effective “using” statement. Next, it reveals the connection string from the contacting new Unlock method of the latest SqlConnection target. 2nd, it monitors the brand new ServerVersion possessions of the SqlConnection to see if or not the new SQL Servers supports MARS. In the event your ServerVersion property productivity a major types of “09”, you safely can be believe that SQL Machine supports MARS.
The latest code second brings cases of the SqlCommand object and you can assigns these to the latest categoryCommand and you can productCmd variables, correspondingly. On top of that, additionally adds the new CategoryID factor to your productCmd adjustable. Following, it works brand new ask included in the categoryCommand target by invoking the fresh ExecuteReader variety of the newest categoryCommand target. It catches the outcome of one’s SQL query execution into the a great SqlDataReader varying right after which loops as a result of all facts where SqlDataReader object.
The new code adds the class title towards PlaceHolder handle thanks to an excellent LiteralControl after which retrieves these products per classification by the invoking the latest ExecuteReader variety of new productCmd object. Should your Jersey City escort girl productReader object consists of one legitimate rows, it simply studies binds you to object which have a good dynamically composed GridView control. When you’re starting new GridView handle, moreover it kits various features of your own GridView manage, including Apparent, BackColor, and you may ForeColor. In the event the productReader object has no valid rows, it just screens the message: “No Situations Utilized in these kinds.”
For many who look towards above Web function having fun with a browser, you will see new output presented inside Figure step one.