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Microsoft ActiveX Data Objects ('''ADO''') is a set of Component Object Model objects for accessing data sources. It provides a layer between Programming Language s and OLE DB (a means of accessing data stores, whether they be Database s or otherwise, in a uniform manner), which allows a developer to write programs which access data, without knowing how the database is implemented. You must be aware of your database for connection only. No knowledge of SQL is required to access a database when using ADO, although one can use ADO to execute arbitrary SQL commands. The disadvantage of this (i.e. using SQL directly) is that it introduces a dependency upon the type of database used. It is positioned as a successor to Microsoft's earlier object layers for accessing data sources, including RDO (Remote Data Objects) and DAO (Data Access Objects). ADO was introduced by Microsoft in October 1996. ADO consists of several top-level objects:
The ADO components are usually used in conjunction with a high-level language such as VBScript in an ASP environment or Visual Basic . However, languages such as Delphi and C++ Builder , development environments from Microsoft rival Borland Software Corporation , also allow the use of ADO to access various databases. In the newer programming framework of .NET , Microsoft also presented an upgraded version of ADO called ADO.NET . Its object structure is quite different from that of traditional ADO. USAGE Some basic steps are required in order to be able to access and manipulate data using ADO : #Create a connection object to connect to the database. #Create a recordset object in order to receive data in. #Open the connection #Populate the recordset by opening it and passing the desired table name or SQL statement as a parameter to ''open'' function. #Do all the desired searching/processing on the fetched data. #Commit the changes you made to the data (if any) by using ''Update'' or ''UpdateBatch'' methods. #Close the recordset #Close the connection ASP Example Here is an ASP example using ADO to select the "Name" field, from a table called "Phonebook", where a "PhoneNumber" was equal to "555-5555". dim myconnection, myrecordset, name set myconnection = server.createobject("ADODB.Connection") set myrecordset = server.createobject("ADODB.Recordset") myconnection.open mydatasource myrecordset.open "Phonebook", myconnection myrecordset.find "PhoneNumber = '555-5555'" name = myrecordset.fields.item("Name") myrecordset.close set myrecordset = nothing set myconnection = nothing This is equivalent to the following ASP code, which uses plain SQL instead of the functionality of the Recordset object: dim myconnection, myrecordset, name set myconnection = server.createobject("ADODB.connection") myconnection.open mydatasource set myrecordset = myconnection.execute("SELECT Name FROM Phonebook WHERE PhoneNumber = '555-5555'") name = myrecordset(0) myrecordset.close set myrecordset = nothing set myconnection = nothing VBA Example This is a Microsoft Access VBA example to update a name of an item, from a table called "items", where "item_code" is equal to "GI8293-23" Dim myconnection as new ADODB.Connection Dim myrecordset as new ADODB.Recordset Set myconnection = CurrentProject.AccessConnection myrecordset.Open "items", myconnection, adOpenKeyset, adLockOptimistic, adCmdTable myrecordset.find "item_code = 'GI8293-23'" if (not myrecordset.EOF) 'If the specified criteria cannot be satisfied, then the current record is EOF myrecordset!item_name = "My New Item" end if myrecordset.update 'Actually commit the update to the data source myrecordset.close myconnection.close SOFTWARE SUPPORT ADO was supported in ASP and in VBA for Office. EXTERNAL LINKS
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