how to generate barcode in c# net with example Now let s try something more complicated that only SQL is able to do. in Font

Creation QR Code ISO/IEC18004 in Font Now let s try something more complicated that only SQL is able to do.

Now let s try something more complicated that only SQL is able to do.
QR-Code Encoder In None
Using Barcode printer for Font Control to generate, create Denso QR Bar Code image in Font applications.
www.OnBarcode.com
Make Data Matrix ECC200 In None
Using Barcode creation for Font Control to generate, create DataMatrix image in Font applications.
www.OnBarcode.com
Event.find( :all, :conditions => "occurs_on < '23-03-2007' OR location NOT LIKE '%Hampton%'" )
Code 39 Creator In None
Using Barcode creation for Font Control to generate, create Code 3 of 9 image in Font applications.
www.OnBarcode.com
Encode EAN-13 Supplement 5 In None
Using Barcode maker for Font Control to generate, create EAN-13 Supplement 5 image in Font applications.
www.OnBarcode.com
Instead of using the = sign, we are using the less-than (<) symbol to make sure that the date occurs after March 23, 2007. This is followed by the SQL OR operator, which says if this first part isn t a match, then try the left-hand side and give it a second chance at matching. Therefore, we check the right-hand side only if the left-hand side fails. If an item fails the occurs_on match, we check to see if the location is NOT LIKE Hampton. You can think of OR as a more permissive joining operator. It only cares that one of the conditions is a match. OR has a sister named AND, which requires that both conditions are true.
GTIN - 128 Drawer In None
Using Barcode encoder for Font Control to generate, create UCC - 12 image in Font applications.
www.OnBarcode.com
Universal Product Code Version A Creator In None
Using Barcode encoder for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
CHAPTER 5 ADVANCED ACTIVE RECORD: ENHANCING YOUR MODELS
USS Code 128 Maker In None
Using Barcode drawer for Font Control to generate, create Code-128 image in Font applications.
www.OnBarcode.com
Printing Ames Code In None
Using Barcode generation for Font Control to generate, create Rationalized Codabar image in Font applications.
www.OnBarcode.com
Event.find( :all, :conditions => "occurs_on < '23-03-2007' AND location NOT LIKE '%Hampton%'" )
QR Code Generation In None
Using Barcode creation for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
QR-Code Recognizer In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
We are also using the SQL LIKE (modified using NOT, for negation) operator, which allows us to make partial matches. Normally, when using =, SQL requires that the string matches perfectly. However, LIKE is more permissive and allows partial matches when used with the % wildcard. Allow us to explain: The % symbols are SQL wildcard characters that apply in LIKE clauses. A % at the beginning of pattern says that the pattern must match at the end of the field (the beginning can be any sequence of characters); a % at the end means that the pattern must match at the beginning, where the end can be any sequence of characters. Using a % on both sides of the pattern means that it must match anywhere in the field. Using %Hampton% means that the word Hampton must occur somewhere (anywhere) in the description. Therefore, a party with the name Big Hampton s Birthday Party would be accepted as a match. As you can see, this usage has all the flexibility of SQL, but it also has SQL s natural limitations. For instance, you may need to find information based on what the user passes into the application via the request parameters in your application (we ll cover request parameters in the next chapter). If you aren t careful, that data can be very dangerous to your application, because it s open to SQL injection attacks. This is when a user submits malicious code that will trick your database server into doing far more than you intended. For more information about SQL injection, check out the Wikipedia article at http://en.wikipedia.org/wiki/SQL_injection. Fortunately, Rails gives us a way to avoid such threats using the array condition syntax, which performs correctly quoted replacements.
Encode UCC-128 In Java
Using Barcode maker for BIRT reports Control to generate, create EAN / UCC - 14 image in BIRT reports applications.
www.OnBarcode.com
UPC-A Supplement 5 Generation In VS .NET
Using Barcode encoder for .NET framework Control to generate, create UPC-A Supplement 5 image in Visual Studio .NET applications.
www.OnBarcode.com
Using an Array
Printing PDF417 In Java
Using Barcode creation for Android Control to generate, create PDF-417 2d barcode image in Android applications.
www.OnBarcode.com
Printing UCC - 12 In Java
Using Barcode encoder for Java Control to generate, create UPC A image in Java applications.
www.OnBarcode.com
The array condition syntax gives you the ability to specify conditions on your database calls in a safer way than using SQL syntax. Also, you don t need to worry so much about SQL specifics like quoting and other concerns, since it does automatic conversions for you on the inputs you give it. This is how it protects against SQL injection it ensures that the substituted values are safely quoted, thereby preventing malicious users from injecting arbitrary SQL into your queries. The following example requires the use of a nice little Ruby method called Date.today. Basically, it returns a Date object that is set to the current date. Let s see if we can find all of the events that occur on this particular day.
Drawing Matrix In VS .NET
Using Barcode printer for .NET Control to generate, create 2D Barcode image in .NET applications.
www.OnBarcode.com
UCC - 12 Printer In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create EAN / UCC - 14 image in ASP.NET applications.
www.OnBarcode.com
>> Event.find(:all, :conditions => ["occurs_on = ", Date.today]).size => 0
UPC - 13 Printer In Objective-C
Using Barcode printer for iPhone Control to generate, create EAN-13 image in iPhone applications.
www.OnBarcode.com
Decode QR Code 2d Barcode In Visual Basic .NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
CHAPTER 5 ADVANCED ACTIVE RECORD: ENHANCING YOUR MODELS
Generate Code 39 In VB.NET
Using Barcode creator for .NET Control to generate, create Code-39 image in .NET applications.
www.OnBarcode.com
Data Matrix 2d Barcode Printer In VS .NET
Using Barcode drawer for .NET Control to generate, create ECC200 image in .NET framework applications.
www.OnBarcode.com
It doesn t look like much is going on today. However, if we had any events that matched today, they would have been returned. Instead of writing in the date, we simply put a in the spot where we would normally write the value we want to find. It took the second element in the array and replaced it where the first appeared. Additionally, the array syntax automatically took our date and converted it into something that our database would like. In fact, we can spy on our log/development.log file and see the conversation.
Event Load (0.113583) SELECT * FROM events WHERE (occurs_on = '2007-03-22')
We gave it a Date object and it turned it into the nice format that pleases our database. If we had passed it a string, it wouldn t have converted at all. We can even pass it some information from another model.
Event.find( :all, :conditions => ["occurs_on = ", Event.find(:first).occurs_on] )
That condition will return all of the events that occur on the same day as the event that we found first. You can pass as many conditions as you want, as long as they occur in the same order as the question marks.
Event.find( :all, :conditions => ["occurs_on = or title like ", Date.today, "%Tiki%"] )
Copyright © OnBarcode.com . All rights reserved.