Techniques of Performing Data Entry

After displaying the table in the SQL Server Enterprise Manager or the Server Explorer, to enter new data, click an empty cell and type the necessary value. After finishing with one cell, you can press Enter, Tab or click another cell. You can start this operation on the most left cell and continue with the cells on its right. When you finish with a row of cells and move to another row, the interpreter creates (or updates) a record. Therefore, entering data also self-creates a record. This also means that, when using the table in the SQL Server Enterprise Manager or the Server Explorer, you will not have to formally create a record of a table: it is automatically created when you enter data.

While performing data entry, the user may skip some fields if the information is not available. The user can skip only columns that allow NULL values. If a column was configured as NOT accepting NULL values, the user must enter something in the field, otherwise he would receive an error and the table would not allow going further.

INSERT TableName VALUES(Column1, Column2, Column_n)

INSERT INTO TableName VALUES(Column1, Column2, Column_n)

In the previous paragraphs, we were stating "you" as if you will be the one performing data entry. In reality, the user will be performing data entry on your products. Therefore, it is your responsibility to reduce, as much as possible, the likelihood of mistakes. Of course, there are various ways, through a "visual" application such as Microsoft Visual C++, etc, that you can take care of this.

INSERT Countries VALUES('Sweden',449964,8875053,'Stockholm','se')

GO

The list of values doesn't have to be typed on the same line. You can use one for each value. Here is example:

INSERT Country

VALUES

(

  'Angola',

  1246700,

  10593171,

  'Luanda',

  'ao'

)

GO

In the same way, the parentheses can be written on their own lines:

INSERT INTO Country VALUES

(

'Mongolia', 1565000, 2694432, 'Ulaanbaator','mn'

)

GO

INSERT Country(CountryName, Capital,InternetCode,Population,Area)

VALUES('Taiwan', 'Taipei', 'tw', 22548009, 35980)

GO

Here is another example:

INSERT

Country(InternetCode, CountryName, Capital,    Area)

VALUES(	'mx',	        'Mexico',       'Mexico', 1972550)

GO

Instead of first creating a table and then performing data entry, you can create a table and add records at once as long as you separate the statements with GO. To proceed, in your code, you must first create the table, which would save it, use GO to end the statement that creates the table, start the statement or each statement used to add a record, and it or each with GO. Consider the following example:

-- =============================================

-- Database: VideoCollection

-- Table:    Videos

-- =============================================

IF EXISTS(SELECT name 

	  FROM 	 sysobjects 

	  WHERE  name = N'Videos' 

	  AND 	 type = 'U')

    DROP TABLE Videos

GO



USE VideoCollection

GO



CREATE TABLE Videos (

VideoTitle varchar(100),

Director varchar(80),

YearReleased int,

VideoLength varchar(30),

Rating varchar(20))

GO



INSERT INTO Videos VALUES('A Few Good Men', 'Rob Reiner', 1992, '138 Minutes', 'R')

GO

INSERT INTO Videos(Director, VideoLength, VideoTitle, YearReleased)

VALUES('Jonathan Dame', '118 Minutes', 'The Silence of the Lambs', 1991)

GO

INSERT INTO Videos(VideoLength, Rating, Director, VideoTitle)

VALUES('112 Minutes', 'R', 'Jonathan Line', 'The Distinguished Gentleman')

GO

INSERT INTO Videos(Rating, VideoTitle, Director, VideoLength)

VALUES('R', 'The Lady Killers', 'Joel Coen & Ethan Coen', '104 Minutes')

GO

INSERT INTO Videos VALUES('Ghosts of Mississipi', 'Rob Reiner', 1996, '130 Minutes', '')

GO

To programmatically perform data entry using a SQL statement, create an INSERT statement exactly following the descriptions made for SQL Query Analyzer. Once the statement is ready, pass it as string to a SqlCommand object and execute it with a call to SqlCommand::ExecuteNonQuery().

Practical Learning: Performing Data Entry With a SqlCommand Object

1. Change the design of the form as follows:
    

   Control Name Text GroupBox   New Continent Label   Name: TextBox txtContinentName   Label   Area: TextBox txtContinentArea   Label   Population TextBox txtContinentPopulation   Button btnNewContinent Create New Continent

2. Double-click the Create New Continent button and implement its code as follows:
    

   private: System::Void btnNewContinent_Click(System::Object * sender, System::EventArgs * e) { String *strContinentName = this->txtContinentName->Text; if( strContinentName->Equals(S"") ) { MessageBox::Show(S"You must provide a name for the continent"); return; } String *strInsert = String::Concat(S"INSERT INTO Continents VALUES('", strContinentName, S"', '", this->txtContinentArea->Text, S"', '", this->txtContinentPopulation->Text, S"');"); SqlConnection *conDatabase = new SqlConnection(S"Data Source=(local);Database='CountriesStats';Integrated Security=yes"); SqlCommand *cmdDatabase = new SqlCommand(strInsert, conDatabase); conDatabase->Open(); cmdDatabase->ExecuteNonQuery(); conDatabase->Close(); this->txtContinentName->Text = S""; this->txtContinentArea->Text = S""; this->txtContinentPopulation->Text = S""; this->txtContinentName->Focus(); }

3. Execute the application and fill out the form as follows:
    
   
4. Click Create New Continent
5. Close the form and return to your programming environment