Numerous Productive Result Kits (MARS) is another function released having ADO.Web dos.0 enabling you to execute multiple concerns otherwise stored steps using one connection. As a result, numerous send-only, read-only result establishes. In earlier incarnations out of ADO.Websites, you might play only one query at the same time using one commitment. Now, into the regarding SQL Servers 2005 and you will ADO.Net dos.0, you easily is also execute several analytical batches in one single relationship. This particular article helps guide you to make use of MARS into the an enthusiastic ASP.Net Webpage. In addition covers the fresh factors in which MARS is appropriate and you can offer performance gurus.
Thank you for visiting MARS
If you use DataReader in your software, you currently have seen the feared mistake message: “You will find currently an open DataReader regarding the this Union and that need to be signed first.” MARS allows you to avoid so it content by permitting one discover several SqlDataReader stuff on one commitment. MARS allows a credit card applicatoin for several SqlDataReader open for the an association whenever for every single illustration of SqlDataReader are come out-of an alternative demand. Each SqlCommand target you put contributes an extra class to the union.
Automatically, MARS can be obtained only on the is the first SQL Servers version to support MARS. Automatically, MARS is permitted when you use the categories from the Program.Study.SqlClient namespace to connect to SQL Host. not, additionally you normally clearly control this particular feature by using a word few in your commitment sequence. Eg, you could potentially clearly set the latest MultipleActiveResultSets characteristic on the partnership string to Correct the following:
- Carry out an effective SqlConnection object and you may initialize they toward appropriate union string.
- Discover the partnership using the Open sort of brand new SqlConnection object.
- Create individual SqlCommand things towards necessary variables to do the fresh new ask. When you’re creating this new SqlCommand items, be sure to associate all of them with the fresh new in past times authored SqlConnection target.
- Once you have created the SqlConnection target, you then can also be invoke the new ExecuteReader style of the newest SqlCommand target to execute the fresh new inquiries.
- Fundamentally, personal the brand new SqlConnection object by executing new Intimate method.
MARS Execution
The fresh analogy this article presents see site demonstrates how to use ple screens groups and you may device recommendations regarding the Northwind database. For every category your retrieve regarding categories table, you then have a tendency to query the merchandise desk (into classification ID just like the a quarrel) to go back most of the items that fall in for the reason that group. You will observe how exactly to incorporate this new for it circumstance.
Very first, do another type of Web site entitled ed ple.aspx to help you they. Now, customize the password in the ple.aspx file to seem such as the pursuing the:
Take a closer look during the just what traces throughout the a lot more than code manage. Very first, the new password retrieves the partnership string on the internet.config file with the adopting the range:
The above mentioned distinct password retrieves the connection string on the ConnectionStrings area of the web.config document. The relationship sequence try kept in the online.config as follows:
Next, new password initializes the fresh categorySql and productsSql variables on the appropriate SQL comments. Next, it can make an illustration of new SqlConnection target through a “using” report. Following, it opens the partnership string by the getting in touch with this new Open form of the new SqlConnection object. 2nd, they inspections the newest ServerVersion property of one’s SqlConnection to see whether or not the SQL Servers helps MARS. If your ServerVersion property returns a primary version of “09”, your properly is also assume that SQL Machine supports MARS.
The newest password second produces cases of new SqlCommand target and you may assigns them to the brand new categoryCommand and you can productCmd variables, correspondingly. Apart from that, additionally, it adds the brand new CategoryID parameter to your productCmd variable. Next, it executes new ask contained in the categoryCommand target by invoking brand new ExecuteReader type the brand new categoryCommand target. They grabs the outcomes of your SQL ask execution for the an excellent SqlDataReader varying then loops through the records in that SqlDataReader object.
The code contributes the class title toward PlaceHolder control by way of a beneficial LiteralControl immediately after which retrieves these products per classification by the invoking the new ExecuteReader sorts of the new productCmd object. Should your productReader target contains one appropriate rows, it just research attach that target having good dynamically written GridView handle. Whenever you are performing the GridView handle, moreover it sets various features of one’s GridView control, like Obvious, BackColor, and you may ForeColor. When your productReader object doesn’t have appropriate rows, it simply displays the message: “No Facts Found in these kinds.”
If you look to the more than Online form playing with a browser, you will observe the fresh new yields shown within the Profile step 1.
