Creating VB database applications using ADO control - Form Design

[VelMurugan]

we have learned to build VB database applications using data control. However, data control is not a very flexible tool as it could work only with limited kinds of data and must work strictly in the Visual Basic environment. To overcome these limitations, we can use a much more powerful data control in VB known as  ADO control. ADO stands for ActiveX data objects. As ADO is ActiveX-based, it could work in different platforms (different computer systems) and different programming languages. Besides, it could access many different kinds of data such as data displayed in the Internet browsers, email text and even graphics other than the usual relational and non relational database information.

To be able to use ADO data control, you need to insert it into the toolbox. To do this, simply press Ctrl+T to open the components dialog box and select Microsoft ActiveX Data Control 6. After this, you can proceed to build your ADO-based VB database applications.

The following example will illustrate how to build a relatively powerful database application using ADO data control. First of all, name the new  form as frmBookTitle and change its caption to Book Titles- ADO Application.  Secondly, insert the ADO data control and name it as adoBooks and change its caption to book. Next, insert the necessary labels, text boxes and command buttons. The runtime interface of this program is shown in the diagram below, it allows adding and deletion as well as updating and browsing of data.
　


The properties of all  the controls are listed as follow:

Form Name                         frmBookTitle
Form Caption                   Book Titles -ADOApplication
ADO Name                       adoBooks
Label1 Name                    lblApp
Label1 Caption                 Book Titles
Label 2 Name                   lblTitle
Label2 Caption                 Title :
Label3 Name                    lblYear
Label3 Caption                 Year Published:
Label4 Name                    lblISBN
Label4 Caption                 ISBN:
Labe5 Name                    lblPubID
Label5 Caption                 Publisher's ID:
Label6 Name                    lblSubject
Label6 Caption                 Subject :
TextBox1 Name                txtitle
TextBox1 DataField           Title
TextBox1 DataSource        adoBooks
TextBox2 Name                txtPub
TextBox2 DataField           Year Published
TextBox2 DataSource        adoBooks
TextBox3 Name                txtISBN
TextBox3 DataField           ISBN
TextBox3 DataSource        adoBooks
TextBox4 Name                txtPubID
TextBox4 DataField           PubID
TextBox4 DataSource        adoBooks
TextBox5 Name                txtSubject
TextBox5 DataField           Subject
TextBox5 DataSource        adoBooks
Command Button1 Name     cmdSave
Command Button1 Caption   &Save
Command Button2 Name      cmdAdd
Command Button2 Caption   &Add
Command Button3 Name     cmdDelete
Command Button3 Caption    &Delete
Command Button4 Name     cmdCancel
Command Button4 Caption    &Cancel
Command Button5 Name     cmdPrev
Command Button5 Caption    &<
Command Button6 Name     cmdNext
Command Button6 Caption    &>
Command Button7 Name     cmdExit
Command Button7 Caption    E&xit

　

To be able to access and manage a database, you need to connect the ADO data control to a database file. We are going to use BIBLIO.MDB that comes with VB6. To connect ADO to this database file , follow the steps below:

a) Click on the ADO control on the form and open up the properties window.

b) Click on the ConnectionString property, the following dialog box will appear.



when the dialog box appear, select the Use Connection String's Option. Next, click build and at the Data Link dialog box, double-Click the option labeled Microsoft Jet 3.51 OLE DB provider.



After that, click the Next button to select the file BIBLO.MDB. You can click on Text Connection to ensure proper connection of the database file. Click OK to finish the connection.



Finally, click on the RecordSource property and set the command type to adCmd Table and Table name to Titles. Now you are ready to use the database file.