qr code generator c# Lesson 2: Using SQLCLR and Filestream in C#

Generation QR Code ISO/IEC18004 in C# Lesson 2: Using SQLCLR and Filestream

Lesson 2: Using SQLCLR and Filestream
Print QR Code In C#.NET
Using Barcode encoder for .NET framework Control to generate, create Denso QR Bar Code image in .NET framework applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Scanner In C#.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
RETURNS BIT AS EXTERNAL NAME TK433ClrDemo."TK433.Clr.Demo".IsRegExMatch;
Encoding Barcode In C#.NET
Using Barcode creator for .NET framework Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
Bar Code Reader In Visual C#.NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Now this function can be used when you want to apply a regular expression in a query. In the following T-SQL example, the query returns the number of rows in the Sales.CreditCard table that do not have a credit card number with exactly 14 numbers. This is done using the regular expression ^[0-9]{14}$:
QR Code JIS X 0510 Drawer In VS .NET
Using Barcode maker for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
www.OnBarcode.com
Draw QR-Code In VS .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create Denso QR Bar Code image in .NET applications.
www.OnBarcode.com
SELECT COUNT(*) AS InvalidCreditCardNumbers FROM Sales.CreditCard WHERE dbo.fnIsRegExMatch(CardNumber, N'^[0-9]{14}$') = 0;
Quick Response Code Encoder In VB.NET
Using Barcode drawer for Visual Studio .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
www.OnBarcode.com
Making Bar Code In C#
Using Barcode creator for .NET framework Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
Here is the result:
Print USS-128 In Visual C#
Using Barcode drawer for .NET Control to generate, create GS1 128 image in VS .NET applications.
www.OnBarcode.com
Code 39 Extended Generation In Visual C#
Using Barcode generation for Visual Studio .NET Control to generate, create Code-39 image in .NET framework applications.
www.OnBarcode.com
InvalidCreditCardNumbers -------------------------0
Draw Matrix Barcode In C#
Using Barcode generation for .NET Control to generate, create Matrix Barcode image in VS .NET applications.
www.OnBarcode.com
Draw Leitcode In C#
Using Barcode printer for VS .NET Control to generate, create Leitcode image in .NET framework applications.
www.OnBarcode.com
Another interesting aspect of CLR (and T-SQL) UDFs is that they can be used in constraints. The following example shows how we can add a check constraint to the Sales.CreditCards table so that it allows only credit card numbers that are NULL or that match the regular expression from the previous example:
Print UPCA In None
Using Barcode printer for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
Encode UPCA In VB.NET
Using Barcode maker for .NET Control to generate, create UPC Code image in Visual Studio .NET applications.
www.OnBarcode.com
ALTER TABLE Sales.CreditCard ADD CONSTRAINT CKCreditCardNumber CHECK(dbo.fnIsRegExMatch(CardNumber, N'^[0-9]{14}$') = 1 OR CardNumber IS NULL);
UPC-A Reader In C#.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Code 128 Code Set A Scanner In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
-- Test the constraint by trying to insert an invalid card number. UPDATE Sales.CreditCard SET CardNumber = '1234' WHERE CreditCardID = 1;
Painting ANSI/AIM Code 128 In VB.NET
Using Barcode printer for .NET Control to generate, create Code 128B image in .NET applications.
www.OnBarcode.com
Printing QR-Code In None
Using Barcode maker for Font Control to generate, create QR Code JIS X 0510 image in Font applications.
www.OnBarcode.com
Here is the error that results:
Creating QR Code In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
www.OnBarcode.com
Drawing ANSI/AIM Code 39 In None
Using Barcode creation for Font Control to generate, create USS Code 39 image in Font applications.
www.OnBarcode.com
Msg 547, Level 16, State 0, Line 1 The UPDATE statement conflicted with the CHECK constraint "CKCreditCardNumber". The conflict occurred in database "AdventureWorks", table "Sales.CreditCard", column 'CardNumber'.
Because we marked the function as both precise (IsPrecise) and deterministic (IsDeterministic) in the CLR code, we can both persist and index a computed column that uses the function. Although the result in this particular example isn t really useful for indexing or persisting, we look at how to go about doing it because it is useful in other cases. To index the result of the function, it must first be placed in the expression of a computed column. In the following T-SQL example, a computed column using the function is added to the table and marked with the persisted attribute. The persisted attribute tells SQL Server to calculate the result of the function only whenever it writes to the underlying column or columns and to store the result of the function physically in the table row. After we add the column, we also create an index on top of it. Note that the computed column does not need to be marked as
290 CHAPTER 7 Extending Microsoft SQL Server Functionality with XML, SQLCLR, and Filestream
persisted for you to be able to index it. The query that is executed against the new column at the end of the example uses the newly created index:
ALTER TABLE Sales.CreditCard ADD IsValidCardNumber AS dbo.fnIsRegExMatch(CardNumber, N'^[0-9]{14}$') PERSISTED; GO
CREATE NONCLUSTERED INDEX IsValidCardNumberIdx ON Sales.CreditCard (IsValidCardNumber); GO
-- This query makes use of the IsValidCardNumberIdx index and performs -- an index seek operation against it. SELECT COUNT(*) FROM Sales.CreditCard WHERE IsValidCardNumber = 1;
Creating a Table-Valued CLR UDF
Because a table-valued UDF returns multiple values (or rather, multiple rows), it is a bit more complex than a scalar UDF. While a scalar UDF consists of a single method, a table-valued UDF consists of two methods:
A method that acts as the iterator or state machine, looping over the values that should be returned as rows A method that is executed for every row and populates the actual row being returned to the SQL Server execution engine
Consider the following CLR code, which defines these two methods for a table-valued UDF. This particular function can be used to split comma-delimited strings.
Why no visual basic .net example
//C#:
his example uses the yield keyword in C# to create an iterator. The yield keyword doesn t exist in Visual Basic .NET, so a Visual Basic .NET code sample is not included. You can create table-valued functions using Visual Basic .NET, but this requires that you create a class that acts as the iterator and handles looping over the values (that is, what yield in C# does for you).
using System; using System.Collections; using System.Collections.Generic;
Copyright © OnBarcode.com . All rights reserved.