how to generate barcode in c# net with example WORKING WITH A DATABASE: ACTIVE RECORD in Font

Printer QR Code 2d barcode in Font WORKING WITH A DATABASE: ACTIVE RECORD

CHAPTER 4 WORKING WITH A DATABASE: ACTIVE RECORD
QR Code ISO/IEC18004 Generation In None
Using Barcode maker for Font Control to generate, create QR Code JIS X 0510 image in Font applications.
www.OnBarcode.com
Paint Barcode In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
>> event.description = "An awesome gay 'ole time with other Rails programmers." => "An awesome gay 'ole time with other Rails programmers."
Encode PDF-417 2d Barcode In None
Using Barcode maker for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
Creating Code 3 Of 9 In None
Using Barcode generator for Font Control to generate, create Code 39 Extended image in Font applications.
www.OnBarcode.com
Note A return of nil always represents nothing. It is a helpful little object that stands in the place of nothingness. If we ask an object for something and it returns false, then false is something so it s not a helpful representation. As a nerdy fact, in logics, false and true are equal and opposite values, but they are values in the end. The same is true of zero (0). The number 0 is not truly nothing. It is an actual representation of an abstract nothing, but it is still something. That s why in programming we have nil (or null in other languages).
Creating Code128 In None
Using Barcode creation for Font Control to generate, create Code 128 Code Set C image in Font applications.
www.OnBarcode.com
Drawing EAN / UCC - 13 In None
Using Barcode creation for Font Control to generate, create GS1 128 image in Font applications.
www.OnBarcode.com
Now when we inspect our Event object, we can see that it has attributes.
Data Matrix Encoder In None
Using Barcode maker for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
UPC - 8 Generation In None
Using Barcode creator for Font Control to generate, create European Article Number 8 image in Font applications.
www.OnBarcode.com
>> event => #<Event:0x23a98e8 @new_record=true, @attributes={"title"=>"RailsConf", "url"=>"http://railsconf.com", "occurs_on"=>"2007-05-17", "description"=>"An awesome gay 'ole time with other Rails programmers.", "location"=>"Portland, Oregon"}>
Printing QR Code In Objective-C
Using Barcode generator for iPhone Control to generate, create QR Code JIS X 0510 image in iPhone applications.
www.OnBarcode.com
QR Code Creation In C#.NET
Using Barcode maker for VS .NET Control to generate, create QR Code image in .NET framework applications.
www.OnBarcode.com
We still haven t written a new record. If you were to look at the events table in the database, it would still be empty. (If you squint really hard at the preceding object inspection string, you ll notice the @new_record variable is still true, and that no id has been assigned yet.) That s because we haven t yet saved the object to the database. Fortunately, saving an Active Record object couldn t be any easier.
USS Code 128 Drawer In None
Using Barcode creation for Software Control to generate, create Code 128 Code Set A image in Software applications.
www.OnBarcode.com
Data Matrix 2d Barcode Creator In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create ECC200 image in ASP.NET applications.
www.OnBarcode.com
>> event.save => true
PDF 417 Printer In .NET Framework
Using Barcode drawer for .NET framework Control to generate, create PDF417 image in VS .NET applications.
www.OnBarcode.com
USS Code 128 Creator In VS .NET
Using Barcode generation for ASP.NET Control to generate, create Code 128 Code Set A image in ASP.NET applications.
www.OnBarcode.com
When you save a new record, a SQL INSERT statement is constructed behind the scenes. If the INSERT was successful, the save operation returns true; if it fails, save returns false. We can ask for a count of the number of rows in the table just to be sure that a record was created.
Code 3/9 Reader In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Printing EAN 128 In Java
Using Barcode creation for Java Control to generate, create EAN 128 image in Java applications.
www.OnBarcode.com
>> Event.count => 1
Making Barcode In Java
Using Barcode encoder for BIRT Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
Barcode Generator In .NET Framework
Using Barcode printer for .NET framework Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Sure enough, we have our first event! You ve got to admit, that was pretty easy. (Now, you might have created some events already during the scaffolding session. If so, don t be surprised if you have more than one event already.) Additionally, if we ask the event
Print Universal Product Code Version A In None
Using Barcode generation for Software Control to generate, create UPC Symbol image in Software applications.
www.OnBarcode.com
Scan UPC Symbol In VB.NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
CHAPTER 4 WORKING WITH A DATABASE: ACTIVE RECORD
whether or not it is a new_record , it will respond with false. Since it s saved, it s not new anymore.
>> event.new_record => false
Let s create another event. This time we ll omit all the chatter from the console so you can get a better sense of how the process plays out. We create a new object and place it in a variable, we set the object s attributes, and finally, we save the record. Note that while we re using the local variable event to hold our object, it can be anything you want. Usually, you ll use a variable that indicates the type of object you re creating, like event, or if you prefer shorthand, just e.
>> event = Event.new >> >> >> >> >> event.title event.location event.url event.description event.occurs_on = = = = = "Jeff's Birthday Party" "Flaming Moe's" 'http://quotedprintable.com' "Bring gifts to *me*!" '2007-10-13'
>> event.save
Note While writer methods look like assignments, they re really methods in disguise. event.title = 'something' is the functional equivalent of event.title=('something'), where title=() is the
method. Ruby provides a little syntactic sugar to make writers look more natural.
Now we re rolling! We ve already created two events and haven t had to write a lick of SQL. Given how easy this is, you might be surprised that we can do it in even fewer steps, but we can. Instead of setting each attribute on its own line, we can pass all of them to new at once. Here s how we could rewrite the preceding process of creating a new record in fewer lines of code:
event = Event.new(:title :location :url :description :occurs_on event.save => => => => => "Jeff's Birthday Party", "Flaming Moe's") "http://quotedprintable.com", "Bring gifts to *me*!", "2007-10-13",
Copyright © OnBarcode.com . All rights reserved.