Hi Kumar,
below are some sample codes that allow you to add, edit & delete records from database.. both the DAO & ADO samples are included.. good luck my fren.. :)
This is not about how to create or design a database, it is about how to connect to a database and manipulate a database using VB. It will work (with some minor alterations) in VBA as well.
There are several ways of connecting to a database (for example, Access), via data bound controls, DAO or ADO. On the whole I do not use data bound controls because I like to keep control of what is happening to the data so the rest is about DAO/ADO.
To start with you need to create a few variables of the following types
Workspace ADODB.Connectio n - This is required if you are using Transaction Processes (I will explain later)
Database - This connects to the database Recordset
ADODB.Recordset - This is the table/query level variable
Field ADODB.Field - This allows us to get info about the fields
Connecting to a Database
With an Access database it is possible to connect to the database in 2 ways, JET or ODBC. Personally I use ODBC because the file management is easier; to change the filename or path just use the ODBC administrator in the control panel.
Note: These examples are here to show what to do very simply, some of the commands have more options than are shown so please review the help files for more details.
DAO example - JET Connection
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Dim ws as Workspace
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Dim db as Database
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Set ws=DBEngine.Workspaces(0)
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set db=ws.OpenDatabase({databasepath and name})
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DAO example - ODBC Connection
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Dim ws as Workspace
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dim db as database
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dim strConnection as string
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set ws=DBEngine.Workspaces(0)
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let strConnection= "ODBC;DSN=" & DatabaseName & ";UID=" & UserName
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& ";PWD=" & UserPassword
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set db=ws.OpenDatabase("", False, False, strConnection)
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ADO Example
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Dim ad as ADODB.Connection
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set ad=New ADODB.Connection
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Let ad.ConnectionString= "ODBC;DSN=" & DatabaseName & ";UID=" &
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UserName & ";PWD=" & UserPassword
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ad.Open
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Opening a Table/Query for Viewing
Now we have the database connection established it is time to look at the data. The following example show how to open a table/query and move through it.
DAO Example
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Dim rs as recordset
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set rs=db.openrecordset({tablename or SQL})
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do while not rs.eof
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'Put the code here for what to do with the information.
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'The field information can be access by the field name
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intID=rs!IDField
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'Or by the order number it is in the list (starting at 0)
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intString=rs.Field(1)
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rs.movenext
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loop
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ADO example
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dim ar as ADODB.recordset
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set ar=new adodb.recordset
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ar.open {SQL Statement}
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do while not ar.EOF
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'Put the code here for what to do with the information.
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'The field information can be access by the field name
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intID=ar!IDField
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'Or by the order number it is in the list (starting at 0)
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intString=ar.Field(1).value
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ar.movenext
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loop
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Change a Record
To edit/add/delete a record we can do it either using SQL or directly. Both DAO and ADO use the execute method for doing updates by SQL.
DAO
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Dim rs as recordset
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set rs=db.openrecordset({tablename or SQL})
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rs.execute "INSERT INTO tb(ID,Name) VALUES (10,Anne)"
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ADO
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dim ar as ADODB.recordset
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set ar=new adodb.recordset
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ar.open {SQL Statement}
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ar.execute "INSERT INTO tb(ID,Name) VALUES (10,Anne)"
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These examples add a new record to the database directly.
DAO - Add New Record
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Dim rs as recordset
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set rs=db.openrecordset({tablename or SQL})
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rs.addnew
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rs!ID=intID
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rs!Name=strName
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rs.update
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ADO - Add new record
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dim ar as ADODB.recordset
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set ar=new adodb.recordset
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ar.open {SQL Statement}
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ar.addnew
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ar!ID=intID
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ar!Name=strName
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ar.update
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These examples show how to edit a record directly, after the recordset is open it checks that there is a record meeting the criteria in the open SQL. If not it creates one.
DAO - Edit record
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Dim rs as recordset
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set rs=db.openrecordset("SELECT * FROM Tb WHERE tdID=10")
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if rs.eof then
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rs.addnew
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else
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rs.edit
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end if
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rs!ID=intID
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rs!Name=strName
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rs.update
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ADO - Edit Record
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dim ar as ADODB.recordset
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set ar=new adodb.recordset
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ar.open "SELECT * FROM Tb WHERE tdID=10"
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if ar.eof then
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ar.addnew
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else
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ar.edit
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end if
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ar!ID=intID
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ar!Name=strName
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ar.update
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These examples show how to delete a record directly, after the recordset is open it checks that there is a record meeting the criteria in the open SQL. If not it does not do a delete.
DAO - Delete Record
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Dim rs as recordset
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set rs=db.openrecordset("SELECT * FROM Tb WHERE tdID=10")
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if not rs.eof then
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rs.delete
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end if
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ADO - Delete Record
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Dim ar as ADODB.recordset
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set ar=new adodb.recordset
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ar.open "SELECT * FROM Tb WHERE tdID=10"
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if not ar.eof then
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ar.delete
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end if
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Note: If you open an object when you have finished with it, close it and set it to nothing. For example...
This is good programming practice and clears the memory.
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