The ADO Data Control

1
The ADO Data Control
2
Universal Data Access

• Open Database Connectivity (ODBC)
• standard for accessing data in databases
• OLE-DB
• allows access to data in many formats
• faster and easier to use than ODBC

3
Application
ADO
OLE-DB

OLE-DB Provider
OLE-DB Provider
OLE-DB Provider
OLE-DB Provider
OLE-DB Provider
ODBC
ODBC Data
Access
SQL Server
Oracle
Excel
4
ADO, DAO and RDO in Visual Basic

• In Visual Basic, three data access interfaces are
  available to you
• ActiveX Data Objects (ADO)
• Remote Data Objects (RDO)
• Data Access Objects (DAO)
• Data access technology is constantly evolving,
  and each of the three interfaces represents a
  different stage of development for data access
  technology.
• The latest is ADO. It features a simpler yet
  more flexible object model than either RDO or
  DAO. For new projects, you should use ADO as your
  data access interface.

5
The ADO Object Model

• Four main objects
• Connection the link between the program and the
  data store
• Command allows you to run commands against the
  data store
• Recordset contains all the data returned from a
  specific action on the data store
• Stream allows the manipulation of data held in
  web resources, such as HTML files

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Using the ADO Data Control

• Add the Microsoft ADO Data Control 6.0 (OLEDB)
  component to your project.
• Create an instance of the ADO Data Control on
  your form.
• Connect to a database with the ADO Data Control
  by building a connection string.
• Set the RecordSource property of the ADO Data
  Control
• Create bound controls on your form.

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Building a Connection String

• In the properties window of the ADO Data
  controls choose the ConnectionString property.
• 3 Methods
• From the property pages, choose Use Connection
  String and choose Build
• From the Provider tab in the Data Link Properties
  dialog box, specify which data provider to use.
• use Microsoft Jet 4.0 OLE DB Provider for Access
  databases
• choose Next gtgt to bring up the Connection tab of
  the Data Link Properties dialog box

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Building a Connection String

• Three methods
• Use a data Data Link File
• Use an ODBC Data Source Name
• Use a Connection String

Back
9
Building a Connection String

• From the Connection tab, enter your database name
  and path (or browse for it)
• Leave the default log on
• information
• Test Connection

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Set the RecordSource property of the ADO Data
Control

• In the properties window of the ADO Data
  controls choose the RecordSource property.
• Choose a Command Type
• adCmdUnknown
• adCmdTable
• adCmdText
• adCmdStoredProc
• Select a table or enter
• an SQL statement

11
Creating Bound Controls

• Many different controls that can hold text and
  graphics can be bound to a field in an ADO Data
  control.
• Set the DataSource property of the bound control
  to the ADO Data Control.
• Set the DataField property of the bound control
  to the field you want to display