Web based School
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The second week begins with a very exciting topic--database integration. Communicating
with a database is an integral part of any application. For a Web-based application,
it's essential to provide the users with a way to interact with data and information.
This lesson begins a series of lessons on how to use the features of Visual InterDev
to facilitate communication between the users and their data. ToChapter's lesson provides
an introduction to help you build database communication into your application. Chapter
9, "Using the Visual Data Tools for Maximum Productivity," extends the
scope of toChapter's lesson to show you how to use the Visual Data Tools to enhance your
productivity. To round out the discussion of database integration, you will learn
how to administer your database components on Chapter 10, "Managing Your Database
Components." ToChapter you will receive an overview of how to leverage Visual InterDev to access
your database information. In this overview, you are introduced to the benefits of
database integration and how Visual InterDev seamlessly provides this essential component.
The next part of the lesson explains the Active Data Object model. Visual InterDev
uses this model to provide controls for communicating with the database. The lesson
also explains the different types of datasources that you can establish based on
the Open Database Connectivity (ODBC) standard. The final sections introduce you to several database features of Visual InterDev.
You will learn how to use the Data View to examine and interact with your database
objects. The lesson also outlines the features of the Query Designer and how this
tool can make your life easier. Lastly, you will see an introduction to special design-time
ActiveX controls that are geared specifically at database integration.
Companies and organizations are jumping on board the Internet and intranet cruise
liner at a rapid pace. Specifically, businesses are providing a way for people to
take action. Electronic commerce is expanding at a rapid pace. You can visit your
favorite retailer on the Internet and buy the gift that your family forgot to give
you for your birthChapter. These retailers include new businesses where their only place
of business is the online marketplace. Amazon.com guides is a good example of this
kind of virtual business. Corporations are discovering the power of the intranet to provide applications
for their employees, and are using the power of private intranets to share applications
and information with partnering companies. The thin-client model of a Web-based application
provides a compelling reason to build new applications using this model as well as
to convert existing systems to the Web. All of the aforementioned developments require one central component to make them
useful--data. Whether you're building an electronic commerce application for the
Internet or constructing an intranet to provide applications for your employees,
you must enable the users to interact with the information. The application must
support creating, storing, modifying, and, if necessary, deleting information to
be considered valuable. A database provides the vehicle for storing the information for future use. But
how do you develop applications that can access the database? Visual InterDev provides
some very robust features for accessing the database from your application. You will
be learning about a few of these features in toChapter's lesson. You can use Visual InterDev to rapidly build your application to include database
connectivity. These features are intuitive, powerful, and easy to use. The word "leveraging"
is used in the title for this section. The word leverage refers to the use of a lever
to provide an advantage in the accomplishment of a task. For example, you might use
a physical lever to help you move some heavy object. You might capitalize on a friendship
to get you into the door at some organization or business. Similarly, Visual InterDev
provides the lever to accelerate your development of an interactive, database application.
You should realize the power of the database features over the next few Chapters.
When I speak of database integration, I'm not only talking about being able to
access a database from your Web page, but also using this connection to integrate
the results to create a holistic application for the user. I also am referring to
using a comprehensive development tool to produce these results.
A holistic application refers to an application that provides a complete experience
for the user. If a user places an order for some items, the application should provide
a way for that person to check the status of their order. Also, your application
should integrate the use of the data to provide additional value to the different
types of users. The customer supplies some customer information along with the order. This data
is stored in different tables within your database. You should be able to provide
a way for the business user in the sales department to locate information about the
customer and their order information. The sales manager may want to explore the past
buying habits of this person and determine if he or she is a repeat customer. In
other words, you should use the data and integrate this information throughout your
application to satisfy the request of both external and internal users. Your requirements will vary, however, depending on what type of application you're
building. A public Internet site that provides electronic commerce will be dramatically
different from a private intranet application. Integration of the data is still the
key for both types of applications. An example of an intranet application might be an oil and gas trading system that
facilitates the exchange of oil and gas between energy companies. An energy company
would consist of several departments that work together to complete a trade. First,
an energy trader of company A makes a deal with company B to sell some oil or gas.
Basic data about the deal is recorded, including the product, the price, and other
company B information. Then, company A's contract administration workgroup uses the
deal information to develop a formal contract. The deal information is used as the core of the contract as well as for additional
information concerning the terms and schedule of the contract. Next, the credit department
uses the information to verify the credit history of company B. After the deal is
consummated, company A's scheduling department schedules the transfer of the product
along some medium such as a pipeline or barge. This information is linked to the
transaction so that the accounting department can account for the movement of the
product and send an invoice to company B. The accounting department would use all
of the information that has been captured along the way to create the invoice as
well as to maintain its guides. Integration of data is essential to the completion
of this cycle.
There are many options for providing database connectivity to your Web page. These
options range from simple solutions that don't contain much robustness to the very
powerful tools that are difficult to use. The matrix in Figure 8.1 compares some
of the many options that are available for connecting a Web page to a database. Web-to-database connectivity com-parison matrix. The matrix in Figure 8.1 consists of two axes. The horizontal axis measures the
capability of the features of the tool and ranges on a scale from Low to High. The
vertical axis describes the ease of use and again ranges from Low to High. I have
rated each tool in the comparison on both of these scales to determine its position
in the matrix. As you can see from the comparison, Visual InterDev is very robust
and easy to use. Java applications and applets rate slightly higher than Visual InterDev
on the capability scale due to their portability across platforms. These same tools
rate lower on their ease of use due to the nature of the Java programming language. Java is very similar to C++ and is, therefore, a more complex language when compared
to a tool like Visual InterDev. The database tools in Visual InterDev are very intuitive
and easy to use because you can visually build your SQL. Visual InterDev also receives high marks for its ability to provide a single environment
for constructing both the Web page and the database calls for your application. With
earlier database solutions like Internet Database Connector (IDC), you had to create
one file to handle your SQL information and calls and another file to process the
formatted HTML page. API programming receives a high rating on the capability scale but is more difficult
to use than the other solutions. For those CGI pioneers, you're probably unhappy
about the low rating of CGI in the comparison matrix. CGI will still be used as a
solution for connecting to a database. With the advent of APIs that improve the performance
of server connections as well as visual tools that significantly augment the time
it takes to build your database application, CGI is now considered more of a legacy.
Now that I have illustrated where Visual InterDev compares with other database
connectivity tools, I will outline some specific benefits of the database features
included with Visual InterDev. The benefits of having an integrated development environment
to create your application can't be understated. You may be familiar with some of
the tools that were listed in the Web-to-database connectivity comparison matrix.
With many of these solutions, you have to use separate development environments and
tools to accomplish database connectivity. Visual InterDev provides a comprehensive
and integrated development environment that offers the following features and benefits:
Visual InterDev offers a seamless environment that includes several database tools
under one integrated roof. For this reason, Visual InterDev is very easy to use.
You don't have to migrate between separate tools and environments to build your database
connection and SQL calls as well as your formatted HTML web pages. Also, the Visual
InterDev development environment provides toolbar and menu options to guide you through
the process of adding database functionality into your web page.
Visual InterDev, as the name indicates, provides a visual environment with which
to build your applications. This intuitive environment includes the Visual Data Tools,
which you will learn more about tomorrow. These tools enable you to visually construct
your SQL statements and immediately test the results. MS Access users love the interface
of the tools because of the similarities between the two environments. You discovered
the benefits of a visual tool to build your HTML web pages during the lesson on the
FrontPage Editor for Visual InterDev in First Chapters. The Visual Data Tools provide the
same type of benefits to your database calls. You don't have to know the details
of SQL to construct your queries. For power SQL programmers, the visual nature of
the tools will save you time from programming the mundane and routine queries and
enable you to spend time on the more complex SQL calls.
Visual InterDev provides an environment that enables you to rapidly build database
connectivity and integration into your application. Our modern age requests, and
sometimes demands, instantaneous information all the time. With Visual InterDev,
you can use the database tools to help meet the desire of your users. Visual InterDev
promotes the theory behind rapid application development by supporting both PC desktop
and server databases. You learned on Chapter 3, "Design and Development Considerations," how to
use databases like MS Access and MS SQL Server at different stages of the development
cycle to rapidly build your application. The method involves conducting joint application
design (JAD) sessions with your users, using Visual InterDev and MS Access to build
a working prototype of the application. The database tools enable you to construct
actual ODBC-compliant SQL calls that can eventually be used when you migrate the
application to a more robust production database like MS SQL Server. This method
can facilitate a very iterative and rapid cycle for your development process.
So far, I have talked a lot about the ease of use of the Visual InterDev database
features. Some people seem to think that a product has to be difficult to offer powerful
features, and that a product that is easy to use can't possibly be very robust. Visual
InterDev provides the best of both worlds--robustness and ease of use. You can program
complex SQL directly from within the Visual InterDev environment. For some databases,
you also can edit and manage your database components. Visual InterDev supports all
of the major ODBC-compliant databases including MS SQL Server, Oracle, Sybase, Informix,
IBM DB2/2, MS Access, Microsoft FoxPro, and Borland Paradox.
The ActiveX Data Object (ADO) provides database access for all of the Visual InterDev
database tools. ADO serves as the central model for you to build database interaction
within your web pages. ActiveX Data Objects can supply connections for your web pages
to any ODBC-compliant database. Microsoft implemented ADO specifically to provide
data access across the Web. The main benefits of the ADO model include low memory
overhead and high speed, which are ideal for Web-based applications. ADO enables you to use ActiveX scripting to establish a connection to your datasource.
You also can use ActiveX scripting to customize the properties and methods of an
ActiveX Data Object. ADO supports a variety of data types, including images and binary
large objects (BLOBs). ADO supports transactions, cursors, error handling, and the
use of stored procedures.
The following section provides a brief explanation of ADO. This overview provides
a basic context for you to understand how Visual InterDev provides data access for
your application through the use of ADO. This discussion isn't meant to be an exhaustive
review of ADO and similar data access methods. For an in-depth discussion of these
topics, I would suggest that you visit the Microsoft ADO Web site at and the Microsoft OLE DB Web site at Microsoft designed ActiveX Data Objects, or ADO, to be language-independent objects
for you to access a database from your Web pages. ADO is built on top of the OLE
DB model from Microsoft. For Visual Basic programmers who are familiar with Data
Access Objects (DAO) and Remote Data Objects (RDO), you may think that Microsoft
is playing alphabet soup with so many standards and acronyms. ADO is the successor
to both RDO and DAO. ADO combines the best of previous data access methods with an
object-based standard, and includes the capability of RDO and DAO and extends their
reach to provide data access for the Internet using the OLE model.
The idea behind OLE DB is to provide an object-based interface that makes remote
objects appear as if they were local. You can see how this model would help you in
your development. The goal is to enable you to access your database through helpful
objects that provide seamless access to your database, which could reside on a remote
server or locally on your machine. Figure 8.2 illustrates how ADO and OLE DB work
together to provide database access for a MS SQL Server database. Figure 8.2 presents a configuration for a typical Web-based application built
using Visual InterDev. You can see that the ActiveX Data Object resides within an
Active Server Page on the web server. When the browser sends a request for database
information, the Active Server Page is called, and ADO submits the request via OLE
DB to the database server. MSDA SQL is used to format the ODBC request for the database server. MSDA is an
ODBC-specific SQL language, and both MS Access and MS SQL Server support the use
of it to communicate with their respective datasources. The ODBC driver translates
the MSDA SQL into a specific language for a particular database. The information
is then passed back through this pipeline. The Active Server Page and ADO work together
to format and send the results back to the browser. ADO and OLE DB.
I have mentioned that ADO is an object-based solution. The ADO model includes
seven major objects:
Figure 8.3 illustrates how each of these objects relate to each other. ADO model. In this model, you see that the Connection object is the central object
in the model. Every other object in the model is related to the Connection
object. This hierarchy makes sense, because the other objects can't exist without
a connection to the database. The ADO model isn't an autocratic hierarchy. In other
words, you don't have to create the second tier of objects under a single Connection
object. For example, you could create a Recordset object that is separate
from a previously defined Connection object. The Recordset object
that you define will exist under a newly created Connection object. Although
you aren't confined to a strict hierarchy, you will typically use the structured
nature of the ADO model to provide organization for your objects and code. Before I explain each of these objects, I need to explain the concept of how objects,
properties, and methods work together. Objects contain certain characteristics, or
attributes. These attributes help to define their behavior and composition. Methods
define certain commands that can be carried using these objects to accomplish some
task. These terms are explained in detail on Chapter 13, "Interacting with Objects
and ActiveX Controls."
The Connection object controls your connection to the database. All of
the information about your connection is established with this object. You can customize
the behavior of the Connection object. For example, you can set the timeout
properties and default database for the connection, and you also can specify to open
and close the connection to the database and manage its transaction properties.
The Command object enables you to specify a specific command that you
are going to execute on a database. For example, you could use the Command
object to call a stored procedure. You can create a Command without associating
the object with a previously defined Connection object. This feature is
an example of where ADO differs from previous database access methods. You don't
have to use a hierarchy of objects to carry out your commands. You will want to organize
your objects into a hierarchy, however, when you execute multiple commands against
the same database connection.
You can use the Recordset object to manipulate the records, or rows within
your database tables. A recordset can contain all of the rows within a base table.
A recordset also may consist of the result set from a specific query. The Recordset
object supports both immediate and batch updates. Immediate updates are executed
against the database instantaneously. With batch updates, the changes are saved and
then sent as a batch to the database. Most of the time, you will probably be using
immediate updates. The Recordset object supports the use of four different types of cursors.
These cursors indicate how the user will interact with the information in your database.
The type of cursor that you can use depends on what cursors your database supports. New Term: A cursor establishes the
navigation behavior for the data that is contained in a database. A cursor's relationship
with a database is analogous to the mouse cursor's relationship with a document.
The mouse cursor indicates where you are in a document and where you can go. Similarly,
a cursor defines where you are in the database and where you can go. Table 8.1 represents the four types of cursors that you can use with the Recordset
object, along with a description of each.
The Field object pertains to a particular column within a recordset.
You can use this object to retrieve specific information about the field as well
as change the contents of a particular field.
You can use the Parameter object to specify parameters for executing
a command against the database. For example, you could use this object to designate
the values for the parameters that are passed to a stored procedure on the database.
This object is typically used with the Command object.
The Property object captures specific properties that are defined by
the service provider. The service provider performs the specific services that enable
you to access and query your data. OLE DB service providers can choose to present
additional characteristics, or properties, to the ActiveX Data Object. You can then
use these properties to implement further capability within your application. For
example, you could use the Property object to determine whether a service
provider supported transactions.
The Error object collects error information that is generated from the
database. Any errors that are encountered when attempting to perform a database function
are captured within this object.
ADO provides collections and properties for the objects within the ADO model.
Collections consist of a group of properties for an object. You use properties to
customize the behavior of your objects. Table 8.2 lists the types of collections
that exist for ADO objects.
Each ADO consists of a distinct set of properties. Refer to the ADO help documentation
within Visual InterDev for an alphabetical listing of all of the ADO properties.
Now that you have learned about the underlying data model used by Visual InterDev,
you will get a chance to experience some of the Visual InterDev features that are
supported by the model. The first feature that you will learn how to use is the Data
View. You received an introduction to this feature during the first week. The Data
View enables you to view all of the database objects within a database. These objects
include tables, fields, views, stored procedures, and triggers. You can use the Data
View to access all of these objects from your client machine. You also can use the
Data View to examine detailed information about the database objects including field
types, key structures, and table definitions.
The Data View tab is displayed next to the File tab in the Visual InterDev project
workspace when you connect your project to a datasource. You will learn how to use
a wizard to walk you through this process in the next section entitled "Building
a Connection with a Database Wizard." Visual InterDev uses a live connection
to the database to present the Data View. This connection enables you to interact
directly with the database objects. Figure 8.4 demonstrates the power of the Data
View. Using the Data View to see your database. The best part about the Data View is that it provides a graphical tool for this
interaction that is very intuitive. The Data View works in conjunction with the Query
Designer and the Database Designer (which you learn more about tomorrow) to provide
a robust set of database tools for a developer. The Data View enables you to connect
to any ODBC-compliant database. You can establish multiple connections to different
databases. Table 8.3 examines the icons that are displayed within the Data View, as well
as their meanings
The Data View provides a very intuitive method for examining your database and
its contents. Moreover, you don't have to use a separate database administrator tool
to view these objects. You can develop your application and manipulate your database
objects all within the comforts of your own Visual InterDev home.
You can connect to a database in several ways. The easiest method is to use the
Database Connection Wizard to add a database connection to your project, and this
section walks you through that very procedure.
To insert a database connection into your project, select the Project menu and
choose the Add to Project menu item. The Add to Project submenu displays a list of
choices for you to choose from. Select Data Connection from the list. This action
displays the Select Data Source dialog window. Figure 8.5 illustrates the available
options on the Select Data Source dialog window. Selecting a data- source.
The File Data Source tab display is shown in Figure 8.5. This display enables
you to configure a File datasource name (DSN) for your project. A File DSN enables
you to set up a file-based connection that is local to a specific computer. This
connection can be shared by multiple users. A file-based connection means that the information to connect to the database
is stored in a .dsn file. You must install an ODBC driver on this computer to communicate
with the database. When the database connection is created for your project, the
information in the .dsn file is inserted into the connect string within your global.asa
file. A File DSN is sometimes referred to a "DSN-less" connection, because
connection information is stored within your project--not a separate file. A File
DSN is recommended due to its portability. You don't have to copy or create a DSN
file on the computer when you move the application. The Look In combo box enables you to browse the file system for a datasource.
This combo box defaults to the ODBC\Data Sources\ directory on the computer.
The File DSN listbox displays all of the available datasources within the specified
directory. You can either double-click a datasource within the listbox or select
the item and click OK to connect to the data- source. The New button enables you
to create a new datasource.
The Machine Data Source tab display enables you to establish a machine datasource
for your project. You can create two types of Machine datasources. The first type
is called a User DSN. This type of DSN can only be used by the designated user and
is specific to a machine. A System DSN is the other type of Machine datasource. A
System DSN is specific to a machine but can be shared by multiple users. This information
is stored in the Windows Registry and must migrate with the application if it's moved
to another machine. Figure 8.6 depicts the Machine Data Source tab display. Specifying a Machine Data Source. This window contains a list of machine datasources that are available. You can
select an item from the list and click OK to create a connection to an existing Machine
datasource. You also can create a new Machine datasource by pressing the New button.
You will be prompted to indicate whether you're creating a User DSN or a System DSN.
I stated earlier that for both the File and Machine datasource you could choose
an existing datasource to insert into your project. The datasource will create a
connection, enabling you to interact with the database. This process is straightforward
if you have already established the datasource. This section focuses on showing you
how to create a new datasource. I will continue to walk you through the Database
Connection Wizard windows to create a new File DSN. The process to set up a Machine
datasource is very similar.
When you click the New button from the Select Data Source window, the Create New
Data Source dialog window is displayed. This window enables you to specify the database
driver that will be used to create the new datasource. Figure 8.7 demonstrates an
example of how to specify the datasource type. Selecting a new data- source type. In Figure 8.7, a listbox displays the available drivers for the data type. These
items vary depending on what database drivers you have installed on the machine.
The Advanced button enables you to view the driver information that will be created
for the datasource based on your selection. You can customize this information if
you want to be very specific about the parameters that should be created for the
datasource. You can use the Create New Data Source window to enter this information
directly into the listbox. In this example, I'm going to select the SQL Server driver
to create a new datasource connection to MS SQL Server. After you have made your
selection, click the Next button to display the next dialog window. The next step involves entering a name for your datasource. Figure 8.8 shows the
window for entering this information. Naming the data- source. The name that you enter is used to represent the underlying datasource and database
objects. You should choose a meaningful name that accurately indicates to the user
what kind of information the datasource contains. For example, "Orders"
is a more meaningful name than "MyData."
Once you have entered the name for the datasource, a listbox is displayed, indicating
the choices that you have made. This window specifies the datasource type, name,
and driver. You can click the Back button to go back and change one of the parameters.
Pressing Finish confirms the choices that you have made and creates the new datasource.
You also can click the Cancel button to cancel this process. Figure 8.9 displays
an example of a new File data- source named Publishers that will be created for a
MS SQL Server database. A new File datasource. After you click Finish, a dialog window display prompts you to log in, if necessary,
to the database that you have chosen. Figure 8.10 confirms your new datasource. Confirming your new datasource. From this window, you enter the server, user ID, and password. The Options button
enables you to enter specific datasource information like the name of the database
and the application type. When you click OK, Visual InterDev logs in to the database
and establishes the database connection. Figure 8.11 displays the additional options
that are available from the SQL Server Login window. Logging in to the database. After you confirm the login parameters by pressing OK, the Database Connection
Wizard creates the .dsn file. Figure 8.12 shows the resulting Publishers.dsn file
that was created based on this example. You can select the DSN file from the list and click OK to insert this datasource
connection into your project. You will be prompted to log in, if necessary, to the
server again. After you log in to the server, Visual InterDev creates the connection
and the results are placed into your project.
Figure 8.13 displays the datasource that was created from the preceding example. Selecting the newly created datasource. Examining the results with the Data View. The datasource information is captured in the global.asa file. Listing 8.1 shows
what happens to the global.asa file when a Microsoft SQL Server connection is inserted
into a project.
</SCRIPT> From Listing 8.1, you should be able to see that the
Database Connection Wizard enables you to create a datasource in a few simple steps.
The datasource is placed in the Visual InterDev project workspace, providing a live
connection to your database objects. You can then use the Data View to access the
objects.
The Query Designer is part of the Visual Data Tools included with Visual InterDev.
These tools definitely make the life of a database programmer easier, providing graphical
tools to access the database objects. You will learn how to use the Visual Data Tools
tomorrow, but the following section introduces you to some of the Query Designer's
features.
Once you have created your datasource, you're ready to access the data. The Query
Designer helps you accomplish this task by enabling you to visually specify your
SQL statements. You build your statements by selecting the tables that you want to
use as well as the fields within those tables. As you make your choices, the SQL
statement is constructed. You can view the statement as it is built and make any
changes to the native SQL. You also can test and view the results of your query within
another pane in the Visual InterDev development environment. The Query Designer can
significantly enhance your database development effort. You can use the Query Designer
to drastically reduce your database programming and testing cycle.
To use the Query Designer, click the DataView tab within the Visual InterDev project
workspace. The Data View display tab enables you to see and access all of the objects
for the datasource. You can use the Query Designer to execute queries against the
database, and to specify the tables, columns, and order of the query results. You
can very easily create joins between multiple tables. In addition to queries, you
also can insert, update, and delete data that is contained within the database. You
also can use the Query Designer to execute stored procedures if you're using MS SQL
Server as your database. The following section examines the features of the Query
Designer in a little more detail.
The Query Designer contains four panes that you can use to interact with your
data. The following list indicates the Query Designer panes:
The Diagram pane enables you to work with the database objects to construct a
SQL statement. Using this pane, you can drag and drop tables and views into the workspace.
Figure 8.14 depicts the layout of the Diagram pane. The Diagram pane. As you choose the tables, the Query Designer associates related tables and indicates
table joins through the use of lines between the tables. You can select individual
columns to be included in the SQL statement or select All Columns. For those SQL
programmers, selecting the All Columns option performs a SELECT * to retrieve
all of the columns within the table.
The Grid pane provides a spreadsheet interface to customize the results of the
query. You can designate which columns to show in the result set as well as how to
order and group the results. Figure 8.15 shows the Grid pane for two sample tables.
The SQL pane enables you to view the SQL statement for the tables and options
that you have selected. You can use the SQL Pane to view a SQL statement as well
as to modify the statement. You also can use this pane to create your own SQL statements.
Figure 8.16 displays a SQL statement within the SQL pane. Customizing the results. The SQL pane.
You can use the Results pane to view the data that is returned from the SQL statement.
Based on the query that you construct, this pane displays the results set of the
current query. You can use the Results pane to add, modify, and delete data in the
database. The effects are immediate, because you're using a live connection to access
the database.
Figure 8.17 shows the Results pane as well as the other three Query Designer panes. Displaying the Results pane.
Visual InterDev includes several design-time controls for communicating with a
database. You will see an in-depth lesson on these controls on Chapter 14, "Extending
Web Pages Through Design-Time Controls." You received an introduction to design-time
ActiveX controls during the first week. Design-time controls enable you to set properties
and attributes at the time of design. At runtime, the properties that you set will
perform robust functionality without the overhead of an ActiveX control. The Database design-time controls that are included with Visual InterDev are built
on top of the ADO model. These controls generate much of the script that is necessary
for connecting and executing commands against a database. A good example of a database
design-time control is the Data Command Control. You can insert this control into
your application and then use the Query Designer to build your SQL statements. The
Data Command Control will capture all of the scripting that is necessary to execute
your SQL statements and insert this logic into an Active Server Page. Database design-time controls can provide a lot of power to your application.
You can use these controls to significantly reduce the time that it takes to build
database integration into your application.
This lesson has provided you with an overview of how to communicate with a database
from your Visual InterDev application, setting the stage for tomorrow when you discover
how to use the Visual Data Tools. First, the lesson centered on the benefits of database integration, explaining
integration from a user's--as well as a developer's--point of view. Visual InterDev
can serve as a powerful lever for building database integration into your application.
Next, the lesson uncovered the mystery of the ActiveX Data Object (ADO) model. The
ADO model was explained so that you could understand what Visual InterDev uses behind
the scenes to connect and access the database. You then received an in-depth look
at how to use the Data View to access your database objects. The Data View works
in conjunction with the Visual Data Tools to provide some very robust features for
interacting with the database. Toward the end of toChapter's lesson you learned how to build a database connection
for your project using the Database Connection Wizard. The lesson provided a step-by-step
tour of how to establish this connection. You also learned how to access your data
using the Query Designer once the connection has been built. The lesson explained
the basic Query Designer features and workspace. The final section of the Chapter focused
on Database design-time controls. The lesson presented an introduction to how these
ActiveX controls can be used at design-time to provide robust functionality when
your application is executed.
For toChapter's workshop, I want you to create the datasource that was presented in
the lesson. If you're using a database other than MS SQL Server, create a datasource
connection to your particular database. After you have established the connection,
practice using the Data View and the Query Designer so that you will be familiar
with these tools when you put them to the test during tomorrow's lesson. Try using
all four of the Query Designer panes to produce the desired results from your SQL
statements.
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