Lesson 23: Creating database applications in VB-Part I

Creating database applications in VB-Part I

23.1 Creating Simple Database Application

Visual basic allows us to manage databases created with different database programs such as MS Access, oracle, MySQL and more. In this lesson, we are not dealing with how to create database files but we will see how we can access database files in the VB environment. In the following example, we will create a simple database application which enables one to browse customers' names.  To create this application,  select the data control on the toolbox(as shown in Figure 23.1) and insert it into the new form. Place the data control somewhere at the bottom of the form. Name the data control as data_navigator. To be able to use the data control, we need to connect it to any database. We can create a database file using any database application but I suggest we use the database files that come with VB6. Let's select NWIND.MDB as our database file.

Figure 23.1

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23.2 Connecting Data Control to Database

To connect the data control to this database, double-click the DatabaseName property in the properties window and then click on the button with three dots on the right(as shown in Figure 23.2) to open a file selection dialog as shown in Figure 23.3. From the dialog, search the folders of your hard drive to locate the databse file NWIND.MDB. It is usually placed under Microsoft Visual Studio\VB98\ folder, Select the aforementioned file and now your data control is connected to this database file.

Figure 23.2

Figure 23.3

The next step is to double-click on the RecordSource property to select the customers table from the database file NWIND.MDB, as shown in Figure 23.4. You can also change the caption of the data control to anything, we use Click to browse Customers. After that, we will place a label and change its caption to Customer Name. In addition, insert another label and name it as cus_name and leave the label empty as customers' names will appear here when we click the arrows on the data control. We need to bind this label to the data control for the application to work. To do this, open the label's DataSource and select data_navigator that will appear automatically. One more thing that we need to do is to bind the label to the correct field so that data in this field will appear on this label. To do this, open the DataField property and select ContactName, as shown in Figure 23.5.

Figure 23.4

Figure 23.5

Now, press F5 and run the program. You should be able to browse all the customers' names by clicking the arrows on the data control, as hown in Figure 23.7.

The Design Interface.

Figure 23.6

The Runtime Interface

Figure 23.7

You can also add other fields using exactly the same method. For example, you can add title, company, adress, City, postcode ,telephone number and more to the database browser. Besides, you can design a more professional interface, as shown in Figure 23.8.

Figure 23.

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