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

Encode QR Code in Font WORKING WITH A DATABASE: ACTIVE RECORD

CHAPTER 4 WORKING WITH A DATABASE: ACTIVE RECORD
Quick Response Code Drawer In None
Using Barcode creator for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Generating EAN13 In None
Using Barcode generator for Font Control to generate, create UPC - 13 image in Font applications.
www.OnBarcode.com
Not bad, but we can do even better. The new constructor creates a new object, but it s our responsibility to save it. If we forget to save the object, it will never get written to the database.
Data Matrix Creator In None
Using Barcode drawer for Font Control to generate, create DataMatrix image in Font applications.
www.OnBarcode.com
Draw Code 128 Code Set C In None
Using Barcode drawer for Font Control to generate, create Code-128 image in Font applications.
www.OnBarcode.com
Using the create Constructor
Code-39 Drawer In None
Using Barcode printer for Font Control to generate, create Code-39 image in Font applications.
www.OnBarcode.com
Barcode Creator In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
When you want to create an object and save it in one fell swoop, you can use the create constructor. We ll use it now to create our third event.
Encode GTIN - 12 In None
Using Barcode creator for Font Control to generate, create UCC - 12 image in Font applications.
www.OnBarcode.com
Drawing Intelligent Mail In None
Using Barcode printer for Font Control to generate, create OneCode image in Font applications.
www.OnBarcode.com
>> Event.create(:title => "RuPy Conference", :location => "Poznan, Poland", :url => 'http://rupy.wmid.amu.edu.pl', :description => "See, we can all get along!") :occurs_on => '2007-04-14', => #<Event:0x2284648...>
Encode Denso QR Bar Code In None
Using Barcode generator for Font Control to generate, create Quick Response Code image in Font applications.
www.OnBarcode.com
Printing Quick Response Code In Java
Using Barcode drawer for Java Control to generate, create Denso QR Bar Code image in Java applications.
www.OnBarcode.com
Instead of returning true or false, the create constructor returns the object it created in this case, an Event object. We re actually passing a hash of attributes to the create constructor. While hashes are normally surrounded by curly braces, when a hash is the only argument to a Ruby method, the braces are optional. In fact, we could just have easily created the attributes hash first, and then given that to create.
Code128 Maker In Java
Using Barcode generation for Eclipse BIRT Control to generate, create Code 128 image in BIRT reports applications.
www.OnBarcode.com
Recognizing EAN / UCC - 13 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
>> attributes = { :title :location :url :description :occurs_on >> Event.create(attributes) => #<Event:0x2325610...> => "Jeff's Birthday Party", => "Flaming Moe's" } => "http://quotedprintable.com", => "Bring gifts to *me*!", =>" 2007-04-14",
PDF417 Drawer In Java
Using Barcode drawer for Eclipse BIRT Control to generate, create PDF417 image in BIRT reports applications.
www.OnBarcode.com
Print ECC200 In None
Using Barcode encoder for Office Word Control to generate, create Data Matrix 2d barcode image in Word applications.
www.OnBarcode.com
And let s now see how many events we ve created by doing a count.
UPC A Decoder In Visual C#
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Painting Data Matrix ECC200 In VB.NET
Using Barcode creator for .NET framework Control to generate, create ECC200 image in Visual Studio .NET applications.
www.OnBarcode.com
>> Event.count => 4
EAN-13 Supplement 5 Reader In Visual C#.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Barcode Encoder In VB.NET
Using Barcode generator for VS .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
You re getting the hang of this now. To summarize, when you want to create a new object and save it manually, use the new constructor; when you want to create and save in one operation, use create. We ve already created three new records, which are plenty for now, so let s move on to the next step: finding records.
GTIN - 13 Encoder In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create European Article Number 13 image in Visual Studio .NET applications.
www.OnBarcode.com
UCC - 12 Creator In .NET Framework
Using Barcode generation for .NET framework Control to generate, create EAN 128 image in Visual Studio .NET applications.
www.OnBarcode.com
CHAPTER 4 WORKING WITH A DATABASE: ACTIVE RECORD
Reading (Finding) Records
Now that we have a few events to play with, it s time to practice finding them. Every model class understands the find method. We ve already touched on it briefly, but find is actually quite versatile and accepts a number of options that modify its behavior. Let s start with the basics. find is a class method. That means you use it on the model class rather than an object of that class, just as we did for the new and create constructors. Just like new and create, a find operation, if successful, returns a new object. There are actually three ways to call find: find(:id): Finds a single record by its unique id. find(:first): Finds the first record. find(:all): Finds all records in the table. You can also pass in a hash of options in addition to :id, :first, or :all. These options include :order and :conditions, among others. We ll go through the different ways to call find in turn and explain how to use each.
Finding a Single Record Using an ID
The :id and :first options always return a single record at most. The :id option is specific; you use it when you re looking for a specific record and you know its unique id. If you give it a single id, it will either return the corresponding record (if there is one) or raise an exception (if there isn t). The :first option is a little more forgiving; it returns the first record in the table, or nil if the table is empty, as explained in the next section. You can find a single record using its unique id using find(:id). Here s how it works:
>> Event.find(1) => #<Event:0x2250e10 @attributes={"title"=>"Tiki Party", "url"=>nil, "occurs_on"=>"2007-09-02", "id"=>"1", "description"=>nil, "location"=>"Hampton's Apartment"}>
As you can see, we found the event with the id of 1. (This is our event 1. Your result will show whichever event you entered first.) If we wanted to take a closer look at what was returned, we could store the result in a local variable.
>> => >> => >> => event = Event.find(1) #<Event:0x2555340...> event.id 1 event.location "Hampton's Apartment"
Copyright © OnBarcode.com . All rights reserved.