vb连接数据库
VB连接SQL数据库的方法
VB使用ADO数据库可以分为有源数据库和无源数据库，即是否使用了DSN数据源，如下例：
1、在连接数据库前首先要在VB菜单中“工程”-“引用”从中选择 microsoft activeX Data objects 2.6 library和 microsoft activeX Data objects recordset 2.6两个组件，这是在连接数据前所必做的工作。
2、接下来定义ADO的连接对象，如下所示：
Set conn = New ADODB.Connection
Set rs = New ADODB.Recordset
第一种方法采用的是无源的数据库连接方法
conn.ConnectionString = "Driver={sql server};server=JSZX3-11;uid=sa;pwd=;database=wzc"
conn.ConnectionTimeout = 30
conn.Open
rs.Open "select 用户名,密码 from login where 用户名='" & Trim(Combo1.Text) & "' And 密码='" & Trim(Text1.Text) & "'", conn, adOpenStatic, adLockReadOnly, adCmdText
If rs.EOF = True And rs.BOF Then
m = MsgBox("请重新登录", vbExclamation)
Text1.Text = ""
Text1.SetFocus
Else
Form1.Hide
End If
rs.Close
这是第二种方法连接数据库的方法，这一种方法是采用有源的方法与数据库连接的方法，代码如下所示：
Set conn = New ADODB.Connection
Set rs = New ADODB.Recordset
conn.ConnectionString = "DSN=login;uid=sa;pwd=;"
conn.ConnectionTimeout = 30
conn.Open
rs.Open "select 用户名 from login", conn, adOpenStatic, adLockReadOnly, adCmdText
Dim i As String
For t = 0 To Val(rs.RecordCount) - 1
i = Trim(rs.Fields("用户名").Value)
rs.MoveNext
Combo1.AddItem i
Next t
rs.Close
连接数据库的方法很多很多，只要各位去勇敢的偿试一下，就可以感觉数据库的方法并不是很难，本人以前也很想做这方法的工作，只是学识不深，未能完成胸中大志，如今对这些方法的多少有一些了解，特意为那些初学者以供学习之用。
下面是连接数据库具体代码：
程序代码
Public conn As New ADODB.Connection
Public rs As New ADODB.Recordset
Public addFlag As Boolean
Public Function OpenCn() As Boolean
Dim mag As String
On Error GoTo strerrmag
Set conn = New ADODB.Connection
conn.ConnectionTimeout = 25
conn.Provider = "sqloledb"
conn.Properties("data source").Value = "127.0.0.1" ''服务器的名字
conn.Properties("initial catalog").Value = "chart" ''库名
conn.Properties("integrated security").Value = "SSPI" ''登陆类型
conn.Open
OpenCn = True
addFlag = True
Exit Function
strerrmag:
mag = "Data can''t connect"
Call MsgBox(mag, vbOKCancel, "Error:Data connect")
addFlag = False
End
End Function
Public Sub clocn()
On Error Resume Next
If conn.State <> adStateClosed Then conn.Close
Set conn = Nothing
End Sub
Public Function openrs(ByVal strsql As String) As Boolean ''连接数据库记录集
Dim mag As String
Dim rpy As Boolean
On Error GoTo strerrm
ag
Set rs = New ADODB.Recordset
If addFlag = False Then rpy = True
With rs
.ActiveConnection = conn
.CursorLocation = adUseClient
.CursorType = adOpenKeyset
.LockType = adLockOptimistic
.Open strsql
End With
addFlag = True
openrs = True
Exit Function
strerrmag:
mag = "data not connect"
Call MsgBox(mag, vbOKCancel, "error:connect")
openrs = False
End
End Function
Public Sub clors()
On Error Resume Next
If rs.State <> adStateClosed Then rs.Clone
Set rs = Nothing
End Sub