Data Entry Using a Data Row

	Data Entry Using a Data Row

Introduction

Visual C++ .NET offers a wide range of support for databases. This is also seen in the ability to perform data entry from various options, including from a DataGrid or using Windows controls. Another option you can use is through the data table system.

Because a database is first of all a list of items with in a two-dimensional arrangement, the Microsoft .NET Framework provides the DataTable class. A DataTable object can be used to create any two-dimensional array of items as done in a flat or file-based database (a database that is not based on a database system such as SQL Server, Paradox, or MS Access but with its own ability to create and save records as files, as done in file processing). To arrange its list of items into records, the DataTable class has a Rows property. A row is simply a record. A row is of type DataRow. When you create a new record in a DataTable object, you in fact add a new DataRow object.

Because a DataSet is an object made of DataTable objects, you can retrieve a table from a DataSet, add a new row to it, and then pass the table back to the DataSet to update. This is another way to perform data entry and can be valuable in a client/server multiple workstations environment.

Practical Learning: Performing Data Entry

Open SQL Data Analyzer

To create a new database, type the following:

IF EXISTS (SELECT * 
	   FROM   master..sysdatabases 
	   WHERE  name = N'DaniloPizza')
	DROP DATABASE DaniloPizza
GO

CREATE DATABASE DaniloPizza;
GO

To create a new table, delete the above code and type the following:

USE DaniloPizza
GO
IF EXISTS (SELECT name 
	 FROM    sysobjects 
	 WHERE  name = N'CustomerOrder' 
	 AND       type = 'U')
    DROP    TABLE    CustomerOrder
GO

create table CustomerOrder (
CustomerOrderID int IDENTITY(1, 1) PRIMARY KEY NOT NULL, 
PizzaSize smallint Default 2 NOT NULL,
PriceSmall Decimal(4,2) Default 8.95,
PriceMedium Decimal(4,2) Default 10.75,
PriceLarge Decimal(4,2) Default 12.55,
Pepperoni Bit,
Sausage Bit,
ExtraCheese Bit,
Onions Bit,
Olives Bit
)
GO
INSERT INTO CustomerOrder (PizzaSize, PriceSmall, PriceMedium, PriceLarge, Pepperoni, Sausage, ExtraCheese, Onions, Olives)
VALUES (2, 8.95, 9.55, 12.55, 1, 1, 0, 0, 0);
INSERT INTO CustomerOrder (PizzaSize, PriceSmall, PriceMedium, PriceLarge, Pepperoni, Sausage, ExtraCheese, Onions, Olives)
VALUES (1, 6.75, 8.95, 12.55, 1, 0, 1, 0, 0);
INSERT INTO CustomerOrder (PizzaSize, PriceSmall, PriceMedium, PriceLarge, Pepperoni, Sausage, ExtraCheese, Onions, Olives)
VALUES (3, 8.95, 9.55, 11.25, 0, 1, 0, 0, 1);
INSERT INTO CustomerOrder (PizzaSize, PriceSmall, PriceMedium, PriceLarge, Pepperoni, Sausage, ExtraCheese, Onions, Olives)
VALUES (2, 8.95, 8.55, 12.55, 0, 0, 1, 1, 0);

Open Visual C++ .NET and create a new Windows Forms Application named DataEntry3
From Server Explorer, open the server that holds the above database then expand the Danilo Pizza database followed by the Tables node
Drag the CustomerOrder table and drop it on the form
On the main menu, click Data -> Generate Dataset...
While the New radio button is selected, change the name of the dataset to dsDaniloPizza
Click OK

Design the form as follows:

Control	Text	Name	Other Properties
GroupBox	Pizza Size
RadioButton	Small	rdoSmall	Cursor: Hand
TextBox	8.95	txtPriceSmall	TextAlign: Right
RadioButton	Medium	rdoMedium	Cursor: Hand
TextBox	10.75	txtPriceMedium	TextAlign: Right Checked: True
RadioButton	Large	rdoLarge	Cursor: Hand
TextBox	12.55	txtPriceLarge	TextAlign: Right
GroupBox	Toppings
CheckBox	Pepperoni	chkPepperoni	CheckAlign: MiddleRight Cursor: Hand FlatStyle: Popup
CheckBox	Sausage	chkSausage	CheckAlign: MiddleRight Cursor: Hand FlatStyle: Popup
CheckBox	Extra Cheese	chkExtraCheese	CheckAlign: MiddleRight Cursor: Hand FlatStyle: Popup
CheckBox	Onions	chkOnions	CheckAlign: MiddleRight Cursor: Hand FlatStyle: Popup
CheckBox	Olives	chkOlives	CheckAlign: MiddleRight Cursor: Hand FlatStyle: Popup

Double-click an empty area of the form and change the Load event as follows:

private: System::Void Form1_Load(System::Object *  sender, System::EventArgs *  e)
		 {
			 this->sqlDataAdapter1->Fill(this->dsDaniloPizza1);
		 }

Double-click the Submit followed by the Close buttons

Implement the events as follows:

private: System::Void btnSubmit_Click(System::Object *  sender, System::EventArgs *  e)
		 {
			 Int16 pizzaSize;
			 Double priceSmall, priceMedium, priceLarge;
			 Boolean pepperoni, sausage, extraCheese, onions, olives;

			 // Find out what radio button was clicked
			 if( this->rdoSmall->Checked == true )
				 pizzaSize = 1;
			 else if( this->rdoMedium->Checked == true )
				 pizzaSize = 2;
			 else if( this->rdoLarge->Checked == true )
				 pizzaSize = 3;

			 // Retrieve the values of pizza prices
			 priceSmall  = this->txtPriceSmall->Text->ToDouble(0);
			 priceMedium = this->txtPriceMedium->Text->ToDouble(0);
			 priceLarge  = this->txtPriceLarge->Text->ToDouble(0);

			 // Retrieve the state of each check box
			 pepperoni   = this->chkPepperoni->Checked;
			 sausage     = this->chkSausage->Checked;
			 extraCheese = this->chkExtraCheese->Checked;
			 onions      = this->chkOnions->Checked;
			 olives		 = this->chkOlives->Checked;

			 // Now that a new record has been created, prepare to save it
		 // First create a DataTable variable of the table used in the current DataSet
		DataTable *tblCustOrder = this->dsDaniloPizza1->Tables->Item[S"CustomerOrder"];
			 // Create a new row from the current table
			 DataRow   *rowRecord    = tblCustOrder->NewRow();
			 
			 // Fill the new row with values entered on the form
			 rowRecord->Item[S"PizzaSize"]   = pizzaSize.ToString();
			 rowRecord->Item[S"PriceSmall"]  = priceSmall.ToString();
			 rowRecord->Item[S"PriceMedium"] = priceMedium.ToString();
			 rowRecord->Item[S"PriceLarge"]  = priceLarge.ToString();
			 rowRecord->Item[S"Pepperoni"]   = pepperoni.ToString();
			 rowRecord->Item[S"Sausage"]     = sausage.ToString();
			 rowRecord->Item[S"ExtraCheese"] = extraCheese.ToString();
			 rowRecord->Item[S"Onions"]      = onions.ToString();
			 rowRecord->Item[S"Olives"]      = olives.ToString();

			 // Pass the new record to the table
			 tblCustOrder->Rows->Add(rowRecord);

			 // Update the DataSet with information in the new record
			 this->sqlDataAdapter1->Update(this->dsDaniloPizza1);

			 // In case the user wants to create a new record, reset the controls
			 this->rdoMedium->Checked        = true;
			 this->txtPriceSmall->Text            = S"8.95";
			 this->txtPriceMedium->Text         = S"10.75";
			 this->txtPriceLarge->Text            = S"12.55";
			 this->chkPepperoni->Checked     = false;
			 this->chkSausage->Checked       = false;
			 this->chkExtraCheese->Checked = false;
			 this->chkOnions->Checked          = false;
			 this->chkOnions->Checked          = false;
		 }

private: System::Void btnClose_Click(System::Object *  sender, System::EventArgs *  e)
		 {
			 Close();
		 }

Return to SQL Data Analyzer. Open a new Blank Query Window and type:
SELECT * FROM CustomerOrder GO;
Press F5 to execute
Return to Visual C++ .NET and press Ctrl + F5 to test the application
Create a new record by entering new information then click Submit
Return to SQL Data Analyzer and press F5 to execute the statement again


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