c# print barcode labels Modifying Data in VS .NET

Making QR in VS .NET Modifying Data

Modifying Data
QR Code JIS X 0510 Generation In VS .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR-Code image in .NET applications.
www.OnBarcode.com
Scanning QR Code In Visual Studio .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
You can modify data through CTEs. To demonstrate this capability, first run the code in Listing 4-2 to create and populate the dbo.CustomersDups table with sample data.
Printing Barcode In Visual Studio .NET
Using Barcode generator for VS .NET Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
Barcode Decoder In VS .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Listing 4-2. Creating and populating the CustomersDups table
QR Printer In Visual C#
Using Barcode drawer for VS .NET Control to generate, create QR Code image in .NET applications.
www.OnBarcode.com
QR Code 2d Barcode Generation In .NET
Using Barcode drawer for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
www.OnBarcode.com
IF OBJECT_ID('dbo.CustomersDups') IS NOT NULL DROP TABLE dbo.CustomersDups; GO WITH CrossCustomers AS ( SELECT 1 AS c, C1.* FROM dbo.Customers AS C1, dbo.Customers AS C2 ) SELECT ROW_NUMBER() OVER(ORDER BY c) AS KeyCol, CustomerID, CompanyName, ContactName, ContactTitle, Address, City, Region, PostalCode, Country, Phone, Fax INTO dbo.CustomersDups FROM CrossCustomers; CREATE UNIQUE INDEX idx_CustomerID_KeyCol ON dbo.CustomersDups(CustomerID, KeyCol);
Denso QR Bar Code Generator In Visual Basic .NET
Using Barcode generation for .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
www.OnBarcode.com
GS1 DataBar Limited Generator In Visual Studio .NET
Using Barcode generator for VS .NET Control to generate, create GS1 DataBar image in .NET framework applications.
www.OnBarcode.com
Note that I used a new function called ROW_NUMBER here to create sequential integers that will be used as unique keys. In SQL Server 2000, you can achieve this by using the IDENTITY function in the SELECT INTO statement. I'll discuss this function in detail later in this chapter. Basically, the code in Listing 4-2 creates a table of customers with a lot of duplicate occurrences of each customer. The following code demonstrates how you can remove duplicate customers using a CTE. WITH JustDups AS ( SELECT * FROM dbo.CustomersDups AS C1 WHERE KeyCol < (SELECT MAX(KeyCol) FROM dbo.CustomersDups AS C2 WHERE C2.CustomerID = C1.CustomerID) ) DELETE FROM JustDups;
EAN / UCC - 13 Maker In .NET
Using Barcode maker for .NET Control to generate, create EAN-13 image in .NET applications.
www.OnBarcode.com
Barcode Encoder In Visual Studio .NET
Using Barcode creator for Visual Studio .NET Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
The CTE JustDups has all duplicate rows for each customer, not including the row where KeyCol is the maximum for the customer. Notice that the code in Listing 4-2 creates an index on (CustomerID, KeyCol) to support the filter. The outer query merely deletes all rows from JustDups. After this code is run, the CustomersDups table contains only unique rows. At this point, you can create a primary key or a unique constraint on the CustomerID column to avoid duplicates in the future.
Bar Code Generation In .NET Framework
Using Barcode drawer for Visual Studio .NET Control to generate, create barcode image in VS .NET applications.
www.OnBarcode.com
ITF Creator In Visual Studio .NET
Using Barcode maker for .NET Control to generate, create ANSI/AIM I-2/5 image in .NET applications.
www.OnBarcode.com
Container Objects
UPC-A Supplement 2 Generation In Java
Using Barcode drawer for Java Control to generate, create GS1 - 12 image in Java applications.
www.OnBarcode.com
Recognize PDF417 In VB.NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
CTEs can be used in container objects such as views and inline UDFs. This capability provides encapsulation, which is important for modular programming. Also, I mentioned earlier that CTEs cannot be nested directly. However, you can nest CTEs indirectly by encapsulating a CTE in a container object and querying the container object from an outer CTE. Using CTEs in views or inline UDFs is very trivial. The following example creates a view returning a yearly count of customers: CREATE VIEW dbo.VYearCnt
Paint EAN 13 In None
Using Barcode generation for Excel Control to generate, create GTIN - 13 image in Office Excel applications.
www.OnBarcode.com
Make Barcode In Java
Using Barcode generation for BIRT Control to generate, create barcode image in Eclipse BIRT applications.
www.OnBarcode.com
AS WITH YearCnt AS ( SELECT YEAR(OrderDate) AS OrderYear, COUNT(DISTINCT CustomerID) AS NumCusts FROM dbo.Orders GROUP BY YEAR(OrderDate) ) SELECT * FROM YearCnt; GO
Make Code 39 Extended In Java
Using Barcode creator for Java Control to generate, create Code 3 of 9 image in Java applications.
www.OnBarcode.com
ECC200 Generator In Objective-C
Using Barcode generator for iPad Control to generate, create Data Matrix image in iPad applications.
www.OnBarcode.com
Querying the view, as shown in the following code, returns the output shown in Table 4-14: SELECT * FROM dbo.VYearCnt;
Reading Code-39 In .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Generate Data Matrix ECC200 In None
Using Barcode generator for Office Excel Control to generate, create Data Matrix 2d barcode image in Office Excel applications.
www.OnBarcode.com
Table 4-14. Yearly Count of Customers
OrderYear NumCusts 1996 1997 1998 67 86 81
If you want to pass an input argument to the container objectfor example, return the yearly count of customers for the given employeeyou'd create an inline UDF as follows: CREATE FUNCTION dbo.fn_EmpYearCnt(@EmpID AS INT) RETURNS TABLE AS RETURN WITH EmpYearCnt AS ( SELECT YEAR(OrderDate) AS OrderYear, COUNT(DISTINCT CustomerID) AS NumCusts FROM dbo.Orders WHERE EmployeeID = @EmpID GROUP BY YEAR(OrderDate) ) SELECT * FROM EmpYearCnt; GO
Querying the UDF and providing employee ID 3 as input returns the output shown in Table 4-15: SELECT * FROM dbo.fn_EmpYearCnt(3);
Table 4-15. Yearly
Count of Customers
OrderYear NumCusts 1996 1997 1998 16 46 30
Recursive CTEs
Recursive CTEs represent one of the most significant T-SQL enhancements in SQL Server 2005. Finally, SQL Server supports recursive querying capabilities with pure set-based queries. The types of tasks and activities that can benefit from recursive queries include manipulation of graphs, trees, hierarchies, and many others. Here I'll just introduce you to recursive CTEs. For more information and detailed applications, you can find extensive coverage in 9. I'll describe a recursive CTE using an example. You're given an input EmployeeID (for example, employee 5) from the Employees table in the Northwind database. You're supposed to return the input employee and subordinate employees in all levels, based on the hierarchical relationships maintained by the EmployeeID and ReportsTo attributes. The attributes you need to return for each employee include: EmployeeID, ReportsTo, FirstName, and LastName. Before I demonstrate and explain the recursive CTE's code, I'll create the following covering index, which is optimal for the task: CREATE UNIQUE INDEX idx_mgr_emp_ifname_ilname ON dbo.Employees(ReportsTo, EmployeeID) INCLUDE(FirstName, LastName);
This index will allow fetching direct subordinates of each manager by using a single seek plus a partial scan. Note the included columns (FirstName and LastName) that were added for covering purposes. Here's the recursive CTE code that will return the desired result, which is shown in Table 4-16: WITH EmpsCTE AS ( SELECT EmployeeID, ReportsTo, FirstName, LastName FROM dbo.Employees WHERE EmployeeID = 5 UNION ALL SELECT EMP.EmployeeID, EMP.ReportsTo, EMP.FirstName, EMP.LastName FROM EmpsCTE AS MGR JOIN dbo.Employees AS EMP ON EMP.ReportsTo = MGR.EmployeeID ) SELECT * FROM EmpsCTE;
Copyright © OnBarcode.com . All rights reserved.