how to generate barcode in c# windows application Modifying Data in Visual C#

Creator Denso QR Bar Code in Visual C# Modifying Data

Modifying Data
QR-Code Encoder In Visual C#.NET
Using Barcode generator for .NET Control to generate, create Denso QR Bar Code image in VS .NET applications.
www.OnBarcode.com
Decoding QR Code In Visual C#
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
You can modify data through CTEs. To demonstrate this capability, rst run the code in Listing 6-2 to create and populate the Sales.CustomersDups table with sample data.
Make Bar Code In C#
Using Barcode printer for Visual Studio .NET Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
Decoding Bar Code In C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
LISTING 6-2 Creating and populating the CustomersDups table
QR Code Creation In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
www.OnBarcode.com
Drawing QR Code JIS X 0510 In .NET
Using Barcode maker for .NET Control to generate, create Quick Response Code image in .NET framework applications.
www.OnBarcode.com
IF OBJECT_ID('Sales.CustomersDups') IS NOT NULL DROP TABLE Sales.CustomersDups; GO SELECT custid, companyname, contactname, contacttitle, address, city, region, postalcode, country, phone, fax INTO Sales.CustomersDups FROM Sales.Customers CROSS JOIN (VALUES(1),(2),(3)) AS Nums(n);
QR Code 2d Barcode Drawer In Visual Basic .NET
Using Barcode generation for .NET Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
www.OnBarcode.com
Paint Barcode In Visual C#
Using Barcode maker for Visual Studio .NET Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
6
Matrix Barcode Encoder In C#
Using Barcode generation for .NET Control to generate, create Matrix Barcode image in VS .NET applications.
www.OnBarcode.com
Paint PDF 417 In Visual C#
Using Barcode creator for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in VS .NET applications.
www.OnBarcode.com
Subqueries, Table Expressions, and Ranking Functions
Create Bar Code In C#
Using Barcode creation for Visual Studio .NET Control to generate, create barcode image in VS .NET applications.
www.OnBarcode.com
Leitcode Generation In Visual C#.NET
Using Barcode generation for .NET framework Control to generate, create Leitcode image in .NET applications.
www.OnBarcode.com
The code in Listing 6-2 creates a table of customers with duplicate occurrences of each customer. The following code demonstrates how you can remove duplicate customers using a CTE:
Print ECC200 In .NET Framework
Using Barcode encoder for Reporting Service Control to generate, create Data Matrix image in Reporting Service applications.
www.OnBarcode.com
Generate EAN128 In Java
Using Barcode encoder for BIRT Control to generate, create EAN / UCC - 13 image in BIRT applications.
www.OnBarcode.com
WITH CustsDupsRN AS ( SELECT *, ROW_NUMBER() OVER(PARTITION BY custid ORDER BY (SELECT 0)) AS rn FROM Sales.CustomersDups ) DELETE FROM CustsDupsRN WHERE rn > 1;
Code 39 Full ASCII Generation In None
Using Barcode generator for Word Control to generate, create ANSI/AIM Code 39 image in Office Word applications.
www.OnBarcode.com
Bar Code Printer In .NET
Using Barcode encoder for Reporting Service Control to generate, create bar code image in Reporting Service applications.
www.OnBarcode.com
The CTE CustsDupsRN assigns row numbers (rn column) to number the duplicate rows for each customer. I ll provide more details about the ROW_NUMBER function later in the chapter; for now it suf ces to say that the duplicate rows for each customer are assigned row numbers beginning with the number 1. The DELETE statement then simply deletes all rows where rn is greater than 1. 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 custid column to avoid duplicates in the future. Note that SQL Server also supports modifying data through derived tables. I have to say, though, that I nd the syntax to be unintuitive. You need to de ne the derived table and alias it in a FROM clause, and direct the modi cation against the derived table alias in a separate clause. For example, the following code uses a derived table to handle the task of deleting duplicates:
Make PDF417 In Java
Using Barcode printer for BIRT Control to generate, create PDF-417 2d barcode image in BIRT applications.
www.OnBarcode.com
PDF417 Reader In C#.NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
DELETE FROM CustsDupsRN FROM ( SELECT *, ROW_NUMBER() OVER(PARTITION BY custid ORDER BY (SELECT 0)) AS rn FROM Sales.CustomersDups ) AS CustsDupsRN WHERE rn > 1;
Creating QR Code JIS X 0510 In Java
Using Barcode drawer for Android Control to generate, create QR Code JIS X 0510 image in Android applications.
www.OnBarcode.com
EAN / UCC - 13 Generation In Java
Using Barcode printer for Java Control to generate, create EAN 13 image in Java applications.
www.OnBarcode.com
CTEs in View and Inline Function De nitions
CTEs can be used in container objects such as views and inline UDFs. Views and inline UDFs provide 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:
IF OBJECT_ID('dbo.YearCustCount') IS NOT NULL DROP VIEW dbo.YearCustCount; GO CREATE VIEW dbo.YearCustCount AS WITH CYearCustCount AS ( SELECT YEAR(orderdate) AS orderyear, COUNT(DISTINCT custid) AS numcusts
Inside Microsoft SQL Server 2008: T-SQL Querying
FROM Sales.Orders GROUP BY YEAR(orderdate) ) SELECT * FROM CYearCustCount; GO
Note that in this particular case the CTE is super uous, and you could de ne the view based on the underlying query directly. The purpose of this example is only to demonstrate the syntax. Query the view, as shown in the following code:
SELECT * FROM dbo.YearCustCount;
You get the following output:
orderyear ----------2006 2007 2008 numcusts ----------67 86 81
If you want to pass an input argument to the container object for example, return the yearly count of customers for the given employee you d create an inline UDF as follows:
IF OBJECT_ID('dbo.EmpYearCustCnt') IS NOT NULL DROP FUNCTION dbo.EmpYearCustCnt; GO CREATE FUNCTION dbo.EmpYearCustCnt(@empid AS INT) RETURNS TABLE AS RETURN WITH CEmpYearCustCnt AS ( SELECT YEAR(orderdate) AS orderyear, COUNT(DISTINCT custid) AS numcusts FROM Sales.Orders WHERE empid = @empid GROUP BY YEAR(orderdate) ) SELECT * FROM CEmpYearCustCnt; GO
Query the UDF providing employee ID 3 as input:
SELECT * FROM dbo.EmpYearCustCnt(3) AS T;
You get the following output:
orderyear ----------2006 2007 2008 numcusts ----------67 86 81
6
Subqueries, Table Expressions, and Ranking Functions
Recursive CTEs
SQL Server supports recursive querying capabilities through CTEs. The types of tasks and activities that can bene t 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 nd extensive coverage in 12, Graphs, Trees, Hierarchies, and Recursive Queries. I ll describe a recursive CTE using an example. You re given an input empid (for example, employee 5) from the HR.Employees table in the InsideTSQL2008 database. You re supposed to return the input employee and subordinate employees in all levels, based on the hierarchical relationships maintained by the empid and mgrid attributes. The attributes you need to return for each employee include empid, mgrid, rstname, 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_i_fname_lname ON HR.Employees(mgrid, empid) 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 ( rstname and lastname) that were added for coverage purposes. Here s the recursive CTE code that will return the desired result:
WITH Emps AS ( SELECT empid, mgrid, firstname, lastname FROM HR.Employees WHERE empid = 5 UNION ALL SELECT Emp.empid, Emp.mgrid, Emp.firstname, Emp.lastname FROM Emps AS Mgr JOIN HR.Employees AS Emp ON Emp.mgrid = Mgr.empid ) SELECT * FROM Emps;
This code generates the following output:
empid ----------5 6 7 9 mgrid ----------2 5 5 5 firstname ---------Sven Paul Russell Zoya lastname -------------------Buck Suurs King Dolgopyatova
Copyright © OnBarcode.com . All rights reserved.