ADO - What is ADO

ADO stands for ActiveX Data Objects. It is a Microsoft data access technology used in applications to interact with different types of data sources, such as databases, spreadsheets, and XML files.

1. What is ADO?

ADO is a set of COM (Component Object Model) objects that provide a high-level programming interface to access and manipulate data. It was introduced by Microsoft as part of the MDAC (Microsoft Data Access Components) framework.

Developers use ADO mainly in applications written in VB (Visual Basic), ASP (Active Server Pages), and C++ to interact with data stored in databases like SQL Server, Oracle, Access, etc.

2. Key Features of ADO

  • Easy to use: Simplifies database connectivity and manipulation.

  • Language-independent: Can be used in any language that supports COM (e.g., VB, C++, C#).

  • Supports multiple data sources: Works with SQL Server, Oracle, Access, Excel, and more.

  • Fast and efficient: Optimized for performance compared to older APIs like DAO or RDO.

  • Disconnected architecture: Allows working with data offline using Recordset objects.

3. ADO Architecture

ADO works as a bridge between applications and data providers. The architecture involves three main components:

  • Application → The program that uses ADO to access data.

  • ADO Objects → Components like Connection, Command, Recordset, and Parameter.

  • Data Provider → The database or data source (e.g., OLE DB, SQL Server, Oracle).

4. Common ADO Objects

ADO Object Description Example Use
Connection Establishes a link to the database Open or close a database connection
Command Executes SQL queries or stored procedures Run SELECT, INSERT, UPDATE, etc.
Recordset Holds the results of a query Navigate through rows of data
Parameter Represents input/output parameters in queries Pass values into stored procedures
Error Handles runtime errors Check for failed queries

5. ADO Workflow Example

Here’s a simple VBScript example:

' Create ADO objects
Dim conn, rs
Set conn = CreateObject("ADODB.Connection")
Set rs = CreateObject("ADODB.Recordset")

' Open connection
conn.Open "Provider=SQLOLEDB;Data Source=ServerName;Initial Catalog=MyDB;User ID=sa;Password=1234;"

' Execute query
rs.Open "SELECT * FROM Employees", conn

' Loop through results
Do While Not rs.EOF
    WScript.Echo rs("FirstName") & " " & rs("LastName")
    rs.MoveNext
Loop

' Close objects
rs.Close
conn.Close
Set rs = Nothing
Set conn = Nothing

6. Advantages of ADO

  • Simplifies database programming.

  • Works with multiple data sources.

  • Provides disconnected recordsets.

  • Better performance than DAO and RDO.

7. Disadvantages of ADO

  • Tightly coupled to Microsoft technologies.

  • Limited compared to modern frameworks like ADO.NET.

  • Less secure and outdated for modern web applications.