Transcript The ADO Data Control

The ADO Data Control
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
Application
ADO
OLE-DB
…
OLE-DB
Provider
OLE-DB
Provider
OLE-DB
Provider
OLE-DB
Provider
OLE-DB
Provider
Access
SQL
Server
Oracle
Excel
ODBC
ODBC
Data
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.
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
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.
Building a Connection String
• In the properties window of the ADO Data
control’s 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 >> to bring up the Connection tab of the
Data Link Properties dialog box
Building a Connection String
• Three methods
– Use a data Data Link File
– Use an ODBC Data Source Name
– Use a Connection String
Back
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
Set the RecordSource property of
the ADO Data Control
• In the properties window of the ADO Data control’s
choose the RecordSource property.
• Choose a Command Type
–
–
–
–
adCmdUnknown
adCmdTable
adCmdText
adCmdStoredProc
• Select a table or enter
an SQL statement
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